View Full Version : Piston vs. DI weight comparison
So, there has been quite a bit of speculation regarding the weight differences between DI guns and piston guns.
Some claim as many as 2 to 3 pounds difference (with the piston gun being heavier of course).
So I decided to grab the good old postal scale and do some non-scientific weight measurements to give a few general weights for folks to go off of.
Here are the two uppers weighed. A 14.5 inch govt. profile M4 style barrel, an AAC blackout pinned and welded, a KAC freefloat RAS, with the full BCG installed. Other then that it is as clean as I can get it as all other accessories are user dependent and obviously add more weight.
The other is an MR556 with the barrel profiled to .72 under the handguard, barrel cut to 14.5, and a Gemtech bi-lock pinned and welded. Once again, a full BCG, and slick.
http://img.photobucket.com/albums/v186/grumpym4/DSCI0011.jpg
Here is the MR556 upper with the handguard removed to show barrel profile:
http://img.photobucket.com/albums/v186/grumpym4/DSCI0012.jpg
Here is the DI upper on the scale:
http://img.photobucket.com/albums/v186/grumpym4/DSCI0009.jpg
And here is the MR upper:
http://img.photobucket.com/albums/v186/grumpym4/DSCI0003.jpg
The MR556 upper is 4 lbs, 14.6 oz. The DI upper, with a slightly smaller barrel profile and the M4 stepdown, is 4 lbs, 1.7 oz. A difference of 12.9 oz.
This means that a real HK416 with a govt. profile will be somewhat less then my MR556, and probably around a half a pound heavier then a similar DI gun, if that.
Also, keep in mind that the KAC FF RAS is a damn light rail system as well, which might be skewing the results a little bit.
What does this mean in the greater scheme of things? Not a damned thing as I don't have a "real" 416 upper in my hands. But it's a start.
It's good to collect empirical data but this is an apples to oranges comparison as the barrel profile, handguard and gas system length are different and skew the results.
The difference in weight between the op-rod upper and the inline piston upper will be the difference in weight between the op-rod & gas tube, gas blocks and gas keys and should only be a few ounces.
When weighing uppers for comparison, they both should be otherwise identically equipped.
Still, I applaud you for actually weighing uppers to find out for yourself instead of just repeating what you read on the internet :thank_you2:
Hunter Rose
09-01-12, 13:18
Mistwolf,
I think Grumpy's intent was not an ounce for ounce scientific comparison, but a general view that piston uppers aren't really that much heavier in the real world. Sure, ceterus perebus, a DI upper will be a few ounces lighter, but here you have two closely configured uppers that for all intents and purposes weigh the same.
I took it as a counter view to the oft repeated mantra that piston guns are unnecessarily heavy. Real world they're not really that much heavier.
sinlessorrow
09-01-12, 15:54
Mistwolf,
I think Grumpy's intent was not an ounce for ounce scientific comparison, but a general view that piston uppers aren't really that much heavier in the real world. Sure, ceterus perebus, a DI upper will be a few ounces lighter, but here you have two closely configured uppers that for all intents and purposes weigh the same.
I took it as a counter view to the oft repeated mantra that piston guns are unnecessarily heavy. Real world they're not really that much heavier.
Good job Grumpy I do agree with Mist.
Also ounces=pounds.
If you have rifles with the same exact everythin and one being a piston it will always be heavier but only ounces heavier.
If you have rifles with the same exact everythin and one being a piston it will always be heavier but only ounces heavier.
So, the "piston is heavier" argument is pretty thin then?
"Ounces=Pounds"
Sure, but a few ounces on a gun is NOT going to be the straw that breaks the camels back.
Sure it's not much but one thing to consider is not just the weight but the location of that weight.
With longer handguards accomodating the support hand further out these days we are having to push accessories (if we choose to use them) closer to the muzzle to give breathing room for that hand.
My own personal rifle has a 13.5 Noveske NSR with a DD fixed front sight, Surefire M600c with a Larue offset mount and SR07 tape switch, and a tango down stubby with rail panel attachment. All that stuff (except for the vert grip mount is FORWARD of my grip. None of this is being supported where they could be the most stable and stave off fatigue-between my arms.
Take a 10 pound weight and hold in directly centered in your hand. No problem-I am He-Man. Take that same weight and hold that puny 10 pounder on the edge with just your fingers where most of that weight is forward of your hand....fatigue comes much faster.
Back to the rifle....Now could I change some things around to make it lighter? Sure but I would have to change my support hand grip on the rifle and that I wont do.
Adding a piston would be more unneeded weight on the forward portion of my rifle and I've already got enough crap on it anyway. IMHO thats (the added weight from the piston)something I can live without. That and the other drawbacks to a piston gun. YMMV.
-Jax
Hunter Rose
09-01-12, 23:14
Stupid phone.
Wrong
I have a KAC 14.5 with 1-8x, laser, sling, etc that now equals than my 416 naked*.
A "few ounces" might not be noticeable to one transporting from your safe, or on a flat range. It will be noticed in operational athleticism, sprint distance or longer. In the unlikely event your in the mountains, the arena 99.9% of forces have ceded to the opposition, every ounce is noticeable.
*416's have a much heavier barrel than .70, a more substantial lower with heavier buffer & spring necessitated by the piston upper. 14.5" HK416 weighs 8.24lb per HK website.
From what I understand, the newer 416s are coming with a govt. profile barrel, meaning that the weight differences will be even less then the numbers I posted.
Adding a piston would be more unneeded weight on the forward portion of my rifle and I've already got enough crap on it anyway. IMHO thats (the added weight from the piston)something I can live without. That and the other drawbacks to a piston gun. YMMV.
-Jax
See, that is what it is. Decisions. I wouldn't run the Surefire light, but something lighter on it. And I wouldn't have the light on the gun all the time. That more than compensates for the extra weight of the parts for the piston. And I get the other positive effects of the piston.
Weight & manouverability of the rifle is so dependent on the barrel length and profile, that other factors become quite small in comparison. Piston has really no effect.
Why H&K then has also heavier buffer etc. and weighs more in general? That is what I see as a move towards reliability: they use heavier masses and more gas to make the gun work also when dirty. They use heavier, more durable parts in some places to give them durability. They could have made the gun lighter, no doubt, but they chose not to for a reason.
Damn, had a whole reply typed up, but got a bad gateway error when I hit the submit button.
Here is a short version.
My reply to sinless was a bit sarcastic. I will concede that the HK416 will be heavier than similar DI counterparts. However, my personal opinion is that the extra weight is not a problem. I have not worked at high altitudes, so have not felt the effects of that particular terrain.
Here is a pic of my gun the way I set it up for Afghanistan, "sort of" similar to Dano's setup:
http://img689.imageshack.us/img689/6159/416editmb8.jpg
http://img208.imageshack.us/img208/7717/pc100001ic7v.jpg
It was equipped with:
S&B Short Dot - 570 grams
LaRue LT104 mount - 201 grams
Harris Bipod - 400 grams
LaRue FUG - 137 grams
This totals 1,308 kgs or 2,88lbs. Total weight of my gun was 5,108kgs or 11,26 punds.
Some comparison numbers:
Hk416 16.5" with steel mag: 8,4lbs/3,8kgs
HK416 14.5" with steel mag: 8,24lbs/3,73kgs
KAC SR-16 14.5" with steel mag: 7,17lbs/3,25kgs
The KAC is 1,23lbs lighter than the 16.5" gun and 1,07lbs lighter than the 14.5" gun.
This is noticeable, of course, but not the main culprit in regards to excessive weight for soldiers' total combat load, IMO. If people can hump Minimi's, Mk46's or Mk48's, they can hump the HK416.
Again, it is heavier when compared to similar DI systems, so if that is a concern then a DI will be lighter.
I also whipped out my calipers, and barrel dimensions on our guns are as follows:
Under handguard: 19mm/0.74"
After gas block: 15mm/0.59"
sinlessorrow
09-02-12, 09:33
Damn, had a whole reply typed up, but got a bad gateway error when I hit the submit button.
Here is a short version.
My reply to sinless was a bit sarcastic. I will concede that the HK416 will be heavier than similar DI counterparts. However, my personal opinion is that the extra weight is not a problem. I have not worked at high altitudes, so have not felt the effects of that particular terrain.
Here is a pic of my gun the way I set it up for Afghanistan, "sort of" similar to Dano's setup:
http://img689.imageshack.us/img689/6159/416editmb8.jpg
http://img208.imageshack.us/img208/7717/pc100001ic7v.jpg
It was equipped with:
S&B Short Dot - 570 grams
LaRue LT104 mount - 201 grams
Harris Bipod - 400 grams
LaRue FUG - 137 grams
This totals 1,308 kgs or 2,88lbs. Total weight of my gun was 5,108kgs or 11,26 punds.
Some comparison numbers:
Hk416 16.5" with steel mag: 8,4lbs/3,8kgs
HK416 14.5" with steel mag: 8,24lbs/3,73kgs
KAC SR-16 14.5" with steel mag: 7,17lbs/3,25kgs
The KAC is 1,23lbs lighter than the 16.5" gun and 1,07lbs lighter than the 14.5" gun.
This is noticeable, of course, but not the main culprit in regards to excessive weight for soldiers' total combat load, IMO. If people can hump Minimi's, Mk46's or Mk48's, they can hump the HK416.
Again, it is heavier when compared to similar DI systems, so if that is a concern then a DI will be lighter.
I also whipped out my calipers, and barrel dimensions on our guns are as follows:
Under handguard: 19mm/0.74"
After gas block: 15mm/0.59"
Ounces do equal pounds. Considering I go hiking with my rifle after a few hours of it you come to appreciate saving ounces.
Ounces do equal pounds. Considering I go hiking with my rifle after a few hours of it you come to appreciate saving ounces.
Considering the loads soldiers carry the difference in weight is in the range of half a percent.
Also considering the fact that my service rifle weighs 4.3kg's loaded with iron sights only I find it a bit amusing to hear that a rifle weighing less than 4kg's is too heavy for service. :) I have no problems at all with my rifle and if you ask me, doing arms drills becomes heavy when you do them with heavy AT weapons or machineguns with hundreds of rounds of ammunition.
sinlessorrow
09-02-12, 09:57
Considering the loads soldiers carry the difference in weight is in the range of half a percent.
Also considering the fact that my service rifle weighs 4.3kg's loaded with iron sights only I find it a bit amusing to hear that a rifle weighing less than 4kg's is too heavy for service. :) I have no problems at all with my rifle and if you ask me, doing arms drills becomes heavy when you do them with heavy AT weapons or machineguns with hundreds of rounds of ammunition.
I have not seen anyone say they cannot manage the weight. Even if you can handle it I can almost guarantee every would appreciate a lighter weapon or pack as well. When you are hiking all day with little rest you come to appreciate every ounce you save.
Ounces do equal pounds. Considering I go hiking with my rifle after a few hours of it you come to appreciate saving ounces.
Considering I carry a shit load of other mission essential equipment in addition to body armor and basic combat load, 1 pound +/- on the gun makes no difference.
Try humping a 33lbs M2 Carl Gustav or a 25lbs MG3 and 250 rounds of ammo (another 17lbs), in addition to your basic combat load, then an 8 pound rifle really is childs play in comparison.
Do this for weeks, with little sleep and crappy field rations (in terms of nutrition), and come back to me.
I'm sorry sinlessorrow, but to compare your "couple of hours" of hiking with what we as soldiers do is just plain ignorant.
sinlessorrow
09-02-12, 10:09
Considering I carry a shit load of other mission essential equipment in addition to body armor and basic combat load, 1 pound +/- on the gun makes no difference.
Try humping a 33lbs M2 Carl Gustav or a 25lbs MG3 and 250 rounds of ammo (another 17lbs), in addition to your basic combat load, then an 8 pound rifle really is childs play in comparison.
Do this for weeks, with little sleep and crappy field rations (in terms of nutrition), and come back to me.
I'm sorry sinlessorrow, but to compare your "couple of hours" of hiking with what we as soldiers do is just plain ignorant.
Wouldn't it be nice to have a lighter load? What I am saying is ever lunce you can save is a good thing, I have never met anyone who disagrees with this. When you are having to carry 75+lbs of gear saving 1 pound or so helps.
I was not comparing myself to you so don't take things so personally, I was just using an example. I know you feel since I never served I should have no opinion but I live in America and I have an opinion.
Larry Vickers
09-02-12, 10:21
Arctic1
Nice looking blaster there - I see you are rolling with the short dot as well; since I was heavily involved with both product developments that warms my heart !!!!
Hit me on PM because I would love to ask you some questions about the Norwegian 416's
Be safe
LAV
Man, I thought my hunting pack was heavy so I ditched it. But you guys in service don't have that option.
You might need some of that kit, at night I go back home or to a cabin...
Sinless, I get where you're coming from. Ounces equal pounds. But with what these guys are required to carry, another pound isn't going to be that noticeable. Heavy is trying to manhandle an M2 on a tripod cause "the berm isn't high enough".
Arctic, Jippo, I can't imagine what it would be like to have to pick up and move during excercises. And we are not even going to get into ammo cans...
What were we talking about?
Hunter Rose
09-02-12, 10:39
Sorry but some of this is just dislike of the piston methinks. What I mean is that only in the HK 416 debate world is this 6 oz extra on a rifle so crucial and detrimental to success both stateside and in current AORs. The M4 with SOCOM profile barrel easily adds as much weight as the HK's piston system. Yet I never seem to recall debates on how detrimental this extra weight is or maybe I just missed those posts. Sure the SOCOM profiled M4 is heavier but its still "light enough" to be handy and useable.
I think people get too hung up on these exact ounce measurement. The 416 used too be unnecessarily heavy mainly due to its barrel profile. Now that they've lightened the barrel profile its in the "light enough" range comparable to weights on all other modern assault rifles.
I know you feel since I never served I should have no opinion but I live in America and I have an opinion.
This really has no relevance to the debate, but this is not what I have told you via PM. You can have an opinion, but you don't neccessarily have the experience in order to view things with the right perspective or within the correct context. Continue this via PM, if you want to discuss it further.
I was not comparing myself to you so don't take things so personally, I was just using an example.
You brought up the "hiking" comment, so I was again trying to put it into perspective for you, within the context of Dano's post, a military setting. That is the post my reply was aimed at.
Wouldn't it be nice to have a lighter load? What I am saying is ever lunce you can save is a good thing, I have never met anyone who disagrees with this. When you are having to carry 75+lbs of gear saving 1 pound or so helps.
I'm sorry Mods/Staff, that this is going off topic, but I want to comment on some things with regards to the section I quoted above.
Like I said, 1 pound more or less on the gun does not matter. Is it 1 pound extra for the total combat load? Sure. However, there are MANY areas where saving weight could reduce the overall combat load significantly, more specifically reducing weight of the following items:
-sleeping bags
-comm systems
-batteries for comms
-body armor
-rucks
-thermals
-optics (not gun optics)
-fuel for cookers
and so forth.
The difference between 75 and 74 pounds (your example) is insignificant. By developing and improving the types of gear I outlined above, those 75 pounds could be reduced to maybe 55-60 pounds. That is significant.
And again, I agree that the HK416 is heavier compared to similar DI systems. I disagree that the extra weight, approximately 1 pound, is a back breaker.
Arctic1
Nice looking blaster there - I see you are rolling with the short dot as well; since I was heavily involved with both product developments that warms my heart !!!!
Hit me on PM because I would love to ask you some questions about the Norwegian 416's
Be safe
LAV
Thanks!
PM sent.
sinlessorrow
09-02-12, 11:55
Artic1 I do agree there are other places that could save more weight, but I still stand by my comment that every ounce counts. Decreaseing overall weight of items carried by 15-20 pounds is great, then add another pound from the rifle and even better.
Difference isn't one pound. Difference really is the difference in weight between the oprod and gas pipe which is really minute.
Most of the weight difference is not related to the gun being a piston at all. Already barrel profile will make a lot of that
Difference isn't one pound. Difference really is the difference in weight between the oprod and gas pipe which is really minute.
Most of the weight difference is not related to the gun being a piston at all. Already barrel profile will make a lot of that
Sure, the oprod might not add a lot of weight isolatedly, but the weight difference between a stock 14.5" HK416 and a stock 14.5" KAC SR-16, both with HK steel mags (253 grams), is 1.07lbs. Nobody can argue that.
If HK started implementing changes to the 416, such as thinner/lighter barrel profile like Grumpy has on his MR, lighter buffer etc, then the difference would be smaller.
Failure2Stop
09-02-12, 12:50
Arguing about a single pound on a single item in regards to weight bearing is completely ridiculous.
Typos brought to you via Tapatalk and autocorrect.
Arguing about a single pound on a single item in regards to weight bearing is completely ridiculous.
Typos brought to you via Tapatalk and autocorrect.
Agreed.
there's a 1.5lb difference between hk416 14.5 & KAC sr16 14.5
This is a 23% difference, nearly a 1/4 more weight for the 416. This is a significant %.
I found the heavier HK got me .3moa tighter groups. For my purposes of little significance.
1.5lbs is
- over a loaded magazine of weight
- a secondary weapon, pistol
- more than my load-bearing gear
- almost 1/2 what a ballistic plate weighs
- some shrapnel spreading fireworks
- significant in my realm
IMO Your either a savvy minimalist of sorts, or chewing the cud while the opposition runs rings around you in the hills. Likely your chewing cud in an armored vehicle and have never left a paved road(cause your overweight POS attempt to isolate all dangers vehicle, is unable to navigate the roads and you can't access exactly the places security forces should be going. If your not speaking of an accoutrement of war, but of some ballistic hobby I suppose a lb alone wouldn't matter to you. If you've been waddling around so overloaded like 99% of mil types, your so far behind being combat effective, i suppose it doesn't matter.
I think it'd be cool if there were mini events, biathalon-esq, mini-scrambles.. that would cause a best of breed minimalist evolution in assault rifles and gear.
Reg the HK magazines, in actuality made for the SA80A2 bullpup.. not the hk416 with a much higher cyclic. They weigh 2x what alum ones do and have had SOCOM safety not for combat use notices put out about em.
there's a 1.5lb difference between hk416 14.5 & KAC sr16 14.5
This is a 23% difference, nearly a 1/4 more weight for the 416. This is a significant %.
I don't see how those numbers can be correct. :confused:
According to HK USA's site, the 14.5" HK416 weighs 8.24lbs with magazine:
http://www.hk-usa.com/military_products/hk416_specs.asp
According to KAC's site, the 14.5" SR-16 weighs 3kgs (6.61lbs) without magazine.
http://www.knightarmco.com/sr16.html
In my comparison, I added an HK steel magazine to make it simliar to the HK, and that adds 253 grams (0.55lbs). The total of the KAC will then be 7.17. The difference is 1.07 pounds.
IMO Your either a savvy minimalist of sorts, or chewing the cud while the opposition runs rings around you in the hills. Likely your chewing cud in an armored vehicle and have never left a paved road(cause your overweight POS attempt to isolate all dangers vehicle, is unable to navigate the roads and you can't access exactly the places security forces should be going. If your not speaking of an accoutrement of war, but of some ballistic hobby I suppose a lb alone wouldn't matter to you. If you've been waddling around so overloaded like 99% of mil types, your so far behind being combat effective, i suppose it doesn't matter.
I don't know if that was directed at me, or just a general opinion? If it was directed at me, why the negative impression?
I respect that you are from a totally different work environment than myself, me being GPF and you being SOF. But I can assure you that I do not take lightly on individual packing requirement lists, both 2nd line, 3rd line and 4th line (our rucks), and try to minimize as much as I can, both for myself and for my guys.
But we have a set of operational requirements in terms of self sufficiency before resupply, the way it usually is with GPF maneuver warfare. And I do not think that a SOF approach on things is neccessarily directly applicable.
And I can assure you that I have done more than just ride in an armored vehicle on Ring Road in Afghanistan.
Again, for me, that 1 pound on the gun is a non-issue in the big picture compared to weight saving that could be done in other areas of our fighting/sustainment load.
Reg the HK magazines, in actuality made for the SA80A2 bullpup.. not the hk416 with a much higher cyclic. They weigh 2x what alum ones do and have had SOCOM safety not for combat use notices put out about em.
Agree on the weight issue. Just my basic load in magazine weight is 1,7kg/3,7lbs. If I could cut that in half I would be happy. But thus far we are only allowed to use the HK mags. Haven't had any issues with mine yet though.
Other than the toys we own in real life if you were in the military [joined or conscripted]you would be issued a rifle and that would be what you use. No caliber choice ,no option on weight and no choice of DI or piston. Just a thought.
Difference isn't one pound. Difference really is the difference in weight between the oprod and gas pipe which is really minute.
Most of the weight difference is not related to the gun being a piston at all. Already barrel profile will make a lot of that
Remember that the HK also has a taller receiver, larger gas block etc.
A pound in your hands has more effect than a pound on your back. Ounces are pounds and if weight doesn't increase capability it isn't worth carrying. Even most HK416 proponents won't tell you that it's necessary in 14.5" unsuppressed rifles on a lighter firing schedule.
Failure2Stop
09-02-12, 17:34
IMO Your either a savvy minimalist of sorts, or chewing the cud while the opposition runs rings around you in the hills. Likely your chewing cud in an armored vehicle and have never left a paved road(cause your overweight POS attempt to isolate all dangers vehicle, is unable to navigate the roads and you can't access exactly the places security forces should be going. If your not speaking of an accoutrement of war, but of some ballistic hobby I suppose a lb alone wouldn't matter to you. If you've been waddling around so overloaded like 99% of mil types, your so far behind being combat effective, i suppose it doesn't matter.
This is kind of my point, though it is a little more condescending than what I was getting at.
If you are working/living/traveling in a place that could unexpectedly erupt in gunfire intended to kill you, every pound you carry should be worth it. In my experience, Mk18s don't work as well as 10.5" 416s, especially when going back and forth from suppressed to unsuppressed. To me, the weight increase associated with the 416 was worth it over the Mk18, but I never carried or used one in combat.
If a pound of weight on a carbine is a significant factor in your ability to do your job, you know it. Your point is valid, your considerable knowledge and skill is relevant, and your input is appreciated. There is no one that can say that you are wrong outside of your team, however, arguing about it here with people that are not in your community really doesn't accomplish much. Same too goes for those that don't mind the extra weight. Just because it doesn't matter to you doesn't mean that it is not a significant factor to others and the performance in their application or duty. So, again, if you don't notice the difference in a pound added to your carbine, there isn't much point in arguing with those that do.
Remember that the HK also has a taller receiver, larger gas block etc.
Even most HK416 proponents won't tell you that it's necessary in 14.5" unsuppressed rifles on a lighter firing schedule.
And if you look at what I wrote in my first post to this thread you will see that acknowledged. That weight isn't there because 416 is piston gun, but it is there because the engineers at H&K thought that it would be beneficial.
Without going into further details of the additional weight distribution on a 416 vs. your run-of-the-mill M4, we can just look at the barrel. We know 416 comes with a heavier barrel, we know that heavier barrel copes better with heavy firing cycles and we know it retains accuracy better when hot. This is universal, not related to the manufacturer. Putting same profile barrel on an M4 would result in heavier weight and better performance when hot. Obviously someone at H&K thought that having thicker heavier barrel would be a good idea.
What comes to the other changes H&K did, the same story pretty much applies. Gas piston doesn't require heavier buffer per definition. Using more gas and heavier springs and buffers just increases reliability. H&K went all out for reliability.
This discussion should not be about if a rifle A is heavier than rifle B, but if rifle B is better (reliable, more accurate esp. during heavy firing cycles, and so on and so forth...) to warrant the heavier weight.
So, there has been quite a bit of speculation regarding the weight differences between DI guns and piston guns.
This is the first sentence of the OP. If we are still talking about the OP H&K in itself is a bad example because it is not a M4 with a piston, but an improved M4 with different features (piston being one of them).
A discussion of merits may be interesting in the same way the engineering of automotive racing is interesting. Minimum weight to what performance end.
Many of us don't find a dump-truck or AK47 interesting. Expectedly durable, slow, and lacking precision. The compromises that allow peak performance interest me.
I find a conventional gas gun sufficiently reliable for all purposes. Nicer recoil impulse and lighter. If suppressed run a heavier buffer.
If you want to run 500rds day suppressed day after day, and not deal with cleaning, a piston & associated penalties may be a better choice for you or your institution.
his is the first sentence of the OP. If we are still talking about the OP H&K in itself is a bad example because it is not a M4 with a piston, but an improved M4 with different features (piston being one of them).
The idea of the thread was the difference between DI ARs and Piston ARs. Not ARs and any kind of piston gun out there.
Taken as a whole, the HK, especially being the start of the current piston AR phase, is the perfect gun for these sorts of comparisons.
The idea of the thread was the difference between DI ARs and Piston ARs. Not ARs and any kind of piston gun out there.
Taken as a whole, the HK, especially being the start of the current piston AR phase, is the perfect gun for these sorts of comparisons.
I didn't direct that at you Grumpy. I appreciate this (and other ones, too) technical comparison you made. That comment was made to people saying that a piston gun is a pound (or what ever) heavier than a DI gun. H&K is, but that is not due to it being a piston gun, but due it being a gun designed to be heavier. It has parts that have more material on them thus making them more durable and heavier.
Weapons are compromises, just like any design is a compromise. You gain some and then you lose some. H&K is a good example of piston AR because it is solid design that works as intended bringing forth the good sides of the piston, but people need to look further than just general specs in wikipedia to judge the gun. It is far too easy to say: "416 is a pound heavier -> piston guns are a pound heavier -> piston guns are too heavy." That is not the truth.
Someone, who shoots rifles for a living(his and other people) told me, asked how he compare KAC SR16 to HK416 (after his unit started to replace KAC to HK, but both are still in use), that "it is better to carry KAC, but it is better to shoot HK".
HK was made for those who shoot (and to shoot it a lot), this is for what I believe LAV and his unit originally asked (LAV can easily correct me if I'm wrong). HK made it heavier (in several areas, to improve reliability) with thicker barrel specifically to accommodate this requirement. They did it so good, that they basically did not even need to put any internal mods, to meet IAR requirements for sustained fire and cook-off resistance much better than fancy designs from competitors.
Can piston rifle be lightweight? Of course it can. I actually just have opportunity to shoot one (not AR - MSBS-5.56 Radon) and it was very nice experience. All you need is pencil barrel (fluted to make it even lighter) and lightweight "anything else".
What I want to say, it it is not "op-rod piston system" that makes HK416 heavier that similar "direct impingement piston system" carbines. It is sum of other, conscious, design decisions that make it heavier.
Actually "piston AR" weights more than "DI AR" by "weight of piston plus weight of op-rod assembly plus weight of receiver bushing minus weight of gas tube". I can not found "pounds" here. Ounces maybe.
sinlessorrow
09-03-12, 07:04
Someone, who shoots rifles for a living(his and other people) told me, asked how he compare KAC SR16 to HK416 (after his unit started to replace KAC to HK, but both are still in use), that "it is better to carry KAC, but it is better to shoot HK".
HK was made for those who shoot (and to shoot it a lot), this is for what I believe LAV and his unit originally asked (LAV can easily correct me if I'm wrong). HK made it heavier (in several areas, to improve reliability) with thicker barrel specifically to accommodate this requirement. They did it so good, that they basically did not even need to put any internal mods, to meet IAR requirements for sustained fire and cook-off resistance much better than fancy designs from competitors.
Can piston rifle be lightweight? Of course it can. I actually just have opportunity to shoot one (not AR - MSBS-5.56 Radon) and it was very nice experience. All you need is pencil barrel (fluted to make it even lighter) and lightweight "anything else".
What I want to say, it it is not "op-rod piston system" that makes HK416 heavier that similar "direct impingement piston system" carbines. It is sum of other, conscious, design decisions that make it heavier.
Actually "piston AR" weights more than "DI AR" by "weight of piston plus weight of op-rod assembly plus weight of receiver bushing minus weight of gas tube". I can not found "pounds" here. Ounces maybe.
You do know who Dano is right? I will stay out of the piston vs DI merits but the part in red made me laugh comin right after what Dano typed.
Montrala, the one thing I will say is the HK M4 came about to fix issues with the 10" MK18.
Animal_Mother556
09-03-12, 08:13
You do know who Dano is right?
I know you weren't directing this towards me...but I don't know who it is.
One example of a lightweight (or certainly well BALANCED piston carbine) is the LWRCi SPR with the interesting spiral flutes on the barrel.
TrenchArtisan
09-04-12, 09:20
What about this?:
If you can get away with cleaning/lubricating a little less frequently (with a piston gun), would it be reasonable to say that you could get away carrying around a few ounces less of cleaning solution and lubricant? Thus offsetting the initial weight difference?
Animal_Mother556
09-04-12, 11:15
:suicide:
sinlessorrow
09-04-12, 12:11
What about this?:
If you can get away with cleaning/lubricating a little less frequently (with a piston gun), would it be reasonable to say that you could get away carrying around a few ounces less of cleaning solution and lubricant? Thus offsetting the initial weight difference?
Now thats grasping for straws.
TrenchArtisan
09-04-12, 17:05
Now thats grasping for straws.
Nope. I don't have a horse in that race.
Just an honest question.
ETA: Nevermind. I just went back and read where the OP said the weight difference is approx 12 ounces and some change.
That would mean that you would have to go from carrying one 12 oz bottle of CLP, to carrying no bottles of CLP, and at that point, I wouldn't calling it "grasping for straws" but "asking for trouble".
sinlessorrow
09-04-12, 17:19
Nope. I don't have a horse in that race.
Just an honest question.
ETA: Nevermind. I just went back and read where the OP said the weight difference is approx 12 ounces and some change.
That would mean that you would have to go from carrying one 12 oz bottle of CLP, to carrying no bottles of CLP, and at that point, I wouldn't calling it "grasping for straws" but "asking for trouble".
well considering pistons still require lubrication getting rid of lube for either would be "asking for trouble". Unless you mount your lube to your rifle it has nothing to do with rifle weight.
totenkopf_u64
09-04-12, 19:29
I am unqualified to debate the merits of some of the rifles mentioned here, but I would like to comment on the DI and piston weight issue.
All else being equal, I would not carry even 1oz. more for a piston gun, especially considering where that extra weight is distributed. Again, all else being equal, there is simply no statistically significant benefit over DI.
The most interesting thing about the notorious Extreme Dust Test III (sorry, I have to do this) is hidden within the data itself. People skipped over the whole data portion and went straight to the results; in fact the military's conclusions are even interesting, but were also ignored. The data shows that after a lubricating and "wiping down" the weapons, during the next course of fire, malfunctions on all weapons returned to virtually zero. the M4 got progressively worst after each round before the next lube or clean phase, but was not significantly worse than the other guns until the later rounds.
Now to explain why the additional weight bothers me. My four day, 60 mile trek on the Appalachian trail over the tallest peaks with my brother and a 55lb. ruck was painful as hell. I was ineligible for military service so this is the most strenuous and lengthy journey memory can muster. During the worst climbs, I didn't see the star on my brothers jump wings, or his Ranger tab carrying any of that weight for him. Those ounces add up and then they break you down... I would have loved to take five to lube and wipe down my rifle, especially if it meant even 1oz. of a difference in the load.
That's just my experience, and it certainly isn't analogous to the job our soldiers do, but it is my experience that unnecessary weight is just that. Incidentally, we were doing the hike wrong... too much weight!
To all of you who serve, I hope you make it home safe... and if you see my brother, please take it easy on him ;)
EDIT: clarification.
I am unqualified to debate the merits of some of the rifles mentioned here
Then why post?
And is it just me or does laying out a brothers achievments in some strange attempt to validate your own unqualified opinions, appear a bit unseemingly?
I think i'll listen to the guy who has actually taken one to war.
Larry Vickers
09-05-12, 06:55
I want to jump in here for a second and clarify things for some people; if there were no benefits whatsoever for a piston gun vs a DI gun then Tier One units in our military would not be using them
They are hands down a better option in an SBR format which is preferred in CQB environments
Best bet is to review my 4 criteria for piston vs DI use posted in my SME forum
In addition remain objective on the topic; no one here or on any forum has more personal attachment to piston AR's than I do yet I remain objective and level headed on the topic; calling things the way I see them - why would anyone here act any differently?
Larry Vickers
totenkopf_u64
09-05-12, 07:00
Then why post?
And is it just me or does laying out a brothers achievments in some strange attempt to validate your own unqualified opinions, appear a bit unseemingly?
I think i'll listen to the guy who has actually taken one to war.
Your ability to engage in civil discourse strikes me as sub-juvenile. Seriously, did you even understand my post?
Instead of junking up the thread, just PM me with all of your inflammatory crap.
Failure2Stop
09-05-12, 08:01
I want to jump in here for a second and clarify things for some people; if there were no benefits whatsoever for a piston gun vs a DI gun then Tier One units in our military would not be using them
They are hands down a better option in an SBR format which is preferred in CQB environments
Best bet is to review my 4 criteria for piston vs DI use posted in my SME forum
In addition remain objective on the topic; no one here or on any forum has more personal attachment to piston AR's than I do yet I remain objective and level headed on the topic; calling things the way I see them - why would anyone here act any differently?
Larry Vickers
I think that this is a great way to end this thread.
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