View Full Version : Ideal barrel length for a hypothetical future issued DMR?
Renegade0100
05-07-19, 18:22
This is a thought experiment.
A brief note on background: I have none. I'm just a civi who enjoys the freedoms of being an American, and it's entertaining to think about these things.
My most recent build, a 12.5" BCM "do everything under 250 yards" got me thinking. Historically, excluding Afghanistan, the majority of combat engagements occurred under 100m, with 300m being the max distance in Iraq, for example. Thus, a 12.5" barrel should be more than sufficient for the vast majority of situations and, IMO, represents a near-perfect compromise between length and velocity. Something similar to my build below is what I would imagine the "ideal" service rifle being:
https://i.imgur.com/HRYkP96.jpg
If I were issuing this to defend lives, I'd switch the optic to a T2 and use a real stock. One could make a case for a quality LPVO in place of a red dot, and possibly a Geissele MK8 rail substituting the MCMR (mainly for the added rigidity needed for NV devices/PEQs). That being said, I still think the MCMR is more than adequate for lasers and is strong enough, but that's not really the point of this thread.
So, assuming a 12.5" free-floated rifle is the standard issue, I think it would be necessary for a squad to have some form of long-range capability too. What would a similar DMR look like? I'm leaning towards an 18" or 20" rifle to try and squeeze the maximum velocity out of the cartridge as possible- the AR was designed around a 20" barrel after all. This build would be the same as the 12.5" carbine in every way except for barrel/rail length and optic. While a 16" could work too, I don't see the point in going shorter, as we already have a fairly short mass-issued carbine. A larger difference in length between the two feels appropriate to me, but this can be debated too.
The issued optic can get tricky. I initially thought perhaps a good LPVO 1-8x FFP, but I'm not sure. I'd rather have more magnification. Nightforce makes an interesting 2.5-10x. I also wonder if, in the future, we'll see some new LPVO's that range from 1-10x.
If I were to make an "ideal" DMR right now, I'd probably use a 20" stainless rifle-length barrel, a 15" Geissele MK8 rail w/some kind of bipod (Atlas maybe), and the NF 2.5-10x. The rest of the rifle would be as ambi as possible.
So, my conclusion would be a 12.5" for general issue, and a 20" for precision/DMR work. Thoughts? What's the ideal combo/setup?
I’m confused. You’re talking about your personal civilian AR pistol and “issued” rifles and optics. Issued by who? Issued to who? Maybe you could explain it in a different way. What is the purpose of this thread? What exactly are you wanting to know?
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Renegade0100
05-07-19, 18:37
I’m confused. You’re talking about your personal civilian AR pistol and “issued” rifles and optics. Issued by who? Issued to who? Maybe you could explain it in a different way. What is the purpose of this thread? What exactly are you wanting to know?
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If we could issue an entirely new set of rifles to the U.S. military right now (or it could be for contractors, or even just a squad of dudes), what would be the ideal setup and combination? I'm using my personal build as an example of something I think is an ideal setup for a large array of situations; if I were in control of determining what gets issued to everybody, I would choose something similar to the above build. What would be the DMR equivalent?
We know that the military takes awhile to catch up on civilian trends; innovations and improvements hit our markets years before it gets picked up by Uncle Sam- see the recent adoption of the new URGI Geissele uppers as an example (adopted last year- we've had that stuff for quite a bit prior).
I'm discussing the ideal combination, barrel lengths, and setups for a carbine and DMR to be used in a squad taking into account the quality, modern gear available on the market. Again, this is all hypothetical.
Renegade0100
05-07-19, 19:32
The response thus far has been oddly dismissive; I used the search feature and didn't see anything similar regarding a modern 20" DMR in the context I provided. But, if this is a topic that has been discussed ad nauseam, then by all means close the thread. I suppose M4C isn't interested in hypotheticals. Oh well.
SamuelBLong
05-07-19, 19:51
Ok I’ll bite...
The short answer is that it would look similar to what’s already out there today... ie the Mk12 Mod 1 and the 16” Recce Carbine, with a few updates...
Barrel: When you’re talking about an SPR / DMR, you’re really talking about the 300-600 meter zone. 600 and beyond your snipers are going to pick up.
The argument for a 16” (or even 14.5”) gun with a good accurate barrel is that for the ranges you’re going to encounter the bullet is still going to stay trans-sonic ... leading to a predictable flight path.
18” Barrel does open the possibility of rifle length gas, but mid-length is pretty well shook out at this point.
Remember that the DMR role is 2 faceted - extend the range of your squad / team to hold off mid-range targets, and to be able to hit reduced exposure or precision targets within 600 meters.
A 16” gun meets that need perfectly, and still has a little more oomph to go slightly beyond that. You also get the benefits of lighter weight, better handling, and a shorter overall package.
Optics: I think 8-10x should be the minimum on the top end. Having the extra power of a 3-18 or similar range makes more sense because now you have the ability to not only positively ID targets faster, but also pinpoint the exact placement of your bullet. I’d say a Horus Tremor 3 reticle, but that’s a whole other discussion.
Rail: Go Geissele or go home. It comes down to the barrel nut system. Eliminate any flex where you can.... not only important due to NV and lasers, but also for overall accuracy shooting off of multiple surfaces and eliminating rail flex while loading the bipod.
So there you go... your ideal “new” SPR... stuff already in existence and in-service:
16” Rifle Cut Stainless Barrel 1/7 or 1/8 twist - Bartlein / Krieger / etc
Geissele Rail - 13”
Pinned Geissele Gas Block
Leupold Mk6 3-18 Tremor 3
Surefire Can and Mount.
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Rail: Go Geissele or go home.
:suicide:
Phased plasma rifle in the 40 Watt range. /thread
Well the US Army recently decided it needed to be a version of the HK G28 with a 16" barrel and Geissele rail so whats the question?
http://www.snipercentral.com/us-army-selects-hk-g28-sdmr-role/
So I would say a 16" SR-25 type with a 1-8 scope.
There's no need to change barrel lengths just to get a good gas system configuration these days.
Longer than mid-length EXT gas systems are available that are Optimum for 16" barrels.
The short answer is that it would look similar to what’s already out there today... ie the Mk12 Mod 1 and the 16” Recce Carbine, with a few updates...
Barrel: When you’re talking about an SPR / DMR, you’re really talking about the 300-600 meter zone. 600 and beyond your snipers are going to pick up.
The argument for a 16” (or even 14.5”) gun with a good accurate barrel is that for the ranges you’re going to encounter the bullet is still going to stay trans-sonic ... leading to a predictable flight path.
18” Barrel does open the possibility of rifle length gas, but mid-length is pretty well shook out at this point.
Remember that the DMR role is 2 faceted - extend the range of your squad / team to hold off mid-range targets, and to be able to hit reduced exposure or precision targets within 600 meters.
A 16” gun meets that need perfectly, and still has a little more oomph to go slightly beyond that. You also get the benefits of lighter weight, better handling, and a shorter overall package.
Renegade0100
05-09-19, 11:42
Considering how anemic 5.56 can get at range, wouldn't you want the most velocity that you can reasonably get? 20" doesn't /seem/ too long to me, given that the M16 was our service rifle since Vietnam. Is the shortened length that you get with the 16" justified over the loss in velocity you get when going below 18" or 20" for a DMR role?
Renegade0100
05-09-19, 11:43
Well the US Army recently decided it needed to be a version of the HK G28 with a 16" barrel and Geissele rail so whats the question?
http://www.snipercentral.com/us-army-selects-hk-g28-sdmr-role/
So I would say a 16" SR-25 type with a 1-8 scope.
.308 is a whole different ballgame. I'm asking from the perspective of an ideal 5.56 DMR for magazine/ammo interchangeability.
Free floated M4A1, Geissele SSF, LPVO and a trained designated marksman.
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.308 is a whole different ballgame. I'm asking from the perspective of an ideal 5.56 DMR for magazine/ammo interchangeability.
The Army has recently determined that the”ideal” SDM(DMR to you) rifle is a 16” 7.62x51. Your perspective of it needing to be 5.56 is flawed. As for “ammo interchangeability”, they can easily delink 7.62 from the M240 or Mk48.
Now, I have first hand experience with the SDM M16A4s built by AMU. They were nice rifles, but were a bit of a pain for maneuverability in vehicles and around buildings. A collapsible stock would have helped greatly. And I also think a 16” free float match barrel with a 2-stage match trigger would have been good too. But, so is a 7.62 16” SDM rifle. And a 7.62 will be less affected by wind at 600 meters than 5.56. Plus, the 16” 7.62 will have a suppressor, so the 16” is needed so it won’t be as long as an M110.
Oh, and if you’re looking for ammo commonality with your existing rifle because you want an SDM type rifle for yourself and don’t actually care about the “issued” aspect, you’d be fine with a 16” WOA SDM barrel, free float, LPVO or ACOG, and an SSA-E trigger. That will get you from 300-600 nicely. Sure, you’re giving up about 2-3 inches of travel from 10mph wind at 600 yards with 77 TMK, compared to a 20” barrel. But it’ll do and will handle better. The 20”+ should be if you want to extract every last drop of 5.56 performance and don’t mind sacrificing maneuverability.
The main concern here is training, not equipment. Secondary but still above equipment is manpower, where the DMR comes from and fits in the Squad or Platoon. Most people don't understand the DMR doesn't add someone to the the Platoon.
I think highly specialized rifles are pointless without the DMR being an ASI position at the Platoon level. DMR school should be like the shooting part of sniper school.
The main concern here is training, not equipment. Secondary but still above equipment is manpower, where the DMR comes from and fits in the Squad or Platoon. Most people don't understand the DMR doesn't add someone to the the Platoon.
I think highly specialized rifles are pointless without the DMR being an ASI position at the Platoon level. DMR school should be like the shooting part of sniper school.
Agreed. And I’ve brought it up in multiple threads with similar topics, like mass-issuing LPVOs. The bulk of the non-infantry Force can’t even work a CCO. The infantry guys are better, but not nearly as good as you’d hope.
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The main concern here is training, not equipment. Secondary but still above equipment is manpower, where the DMR comes from and fits in the Squad or Platoon. Most people don't understand the DMR doesn't add someone to the the Platoon.
I think highly specialized rifles are pointless without the DMR being an ASI position at the Platoon level. DMR school should be like the shooting part of sniper school.
In the Army, there is an SDM course. It’s a week long and incorporates points of instruction on kill zones, external and terminal ballistics, reticle usage, range and wind estimation etc..
And the SDM/DMR isn’t a platoon level position, but a squad level position. Essentially one of the two riflemen in the squad gets the SDM rifle. But I do think it would be good to have as an ASI.
In the Army, there is an SDM course. It’s a week long and incorporates points of instruction on kill zones, external and terminal ballistics, reticle usage, range and wind estimation etc..
And the SDM/DMR isn’t a platoon level position, but a squad level position. Essentially one of the two riflemen in the squad gets the SDM rifle. But I do think it would be good to have as an ASI.
A week is nothing compared to what it should be. My division's new marksmanship course was two weeks and did that still didn't feel long enough.
vicious_cb
05-11-19, 17:09
A week is nothing compared to what it should be. My division's new marksmanship course was two weeks and did that still didn't feel long enough.
Pretty much this, its software issue not a hardware one. Talking about rifles is a moot point when you cant even maximize the capability of a standard M4 in the general purpose forces.
A week is nothing compared to what it should be. My division's new marksmanship course was two weeks and did that still didn't feel long enough.
I thought the AMU course was great. There’s always more to learn, but the course got soldiers hitting unknown distance targets out to 800 with M4s even.
That said, there needs to be continued practice. Battalions need to have SDM trainers who can run 600 yard ranges during the train up cycle.
Pretty much this, its software issue not a hardware one. Talking about rifles is a moot point when you cant even maximize the capability of a standard M4 in the general purpose forces.
Well, this is about specific people with better rifles, not every single PVT Snuffy.
Well, this is about specific people with better rifles, not every single PVT Snuffy.
Yeah but all of the money they put into testing new rifles, new calibers, equipping SDMs, and all the other bullshit would be better spent by actually making marksmanship mean something. That shit doesn’t even go on an SRB.
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Renegade0100
05-11-19, 22:29
Yeah but all of the money they put into testing new rifles, new calibers, equipping SDMs, and all the other bullshit would be better spent by actually making marksmanship mean something. That shit doesn’t even go on an SRB.
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I agree with you; however, it's worth noting that this is primarily a gear forum. Discussing rifles and related subject matter is the point.
Back to the original discussion- it seems that the compromise between velocity and maneuverability has came to a general consensus of 16", whether that be 7.62 or 5.56. For the purposes of the thread, I think 5.56 is a more productive conversation. I also think a 5.56 DMR has merit, exemplified by the proliferation of the Mk12, for the same reason that the 249 does in conjunction with the 240B (or now, KAC's new LAMG).
That being said, I still lean towards 18" & 20" in 5.56 DMR for squeezing out as much energy from the round as possible. I've always thought that for a service rifle, you'd go as short as you reasonably could (so, 12.5" probably). For a DMR, I've thought the opposite- go as long as you reasonably could (and thus, 20" makes sense to me due to the M16's service and it being closer to the original design). This is to take the most advantage of the expected engagement distances of each. You guys seem to really favor the 16", so perhaps this logic is flawed.
As a Squad DM, he will spend as much time kicking doors as anyone. If the DM always stays out on overwatch he might as well be in Weapons with the 240s that always stay out.
I don't see much juice being squeezed going from 16" to 20", and I'd prefer not to kick doors with a 20". I also think the Recce is the original DMR, and got it pretty right.
vicious_cb
05-12-19, 03:32
I agree with you; however, it's worth noting that this is primarily a gear forum. Discussing rifles and related subject matter is the point.
You can't talk about guns without the context of its use. Several knowledge people have already told you that focusing minutiae like velocity, ballistics and barrel length don't matter if you don't have the proper training and sustainment in place. Sorry to be a party pooper but threads like this are just ballistic masturbation. Hypothetical "Whats guns should the ultimate squad have?" are better asked on airsoft/mil. cosplay forums. There are still enough real world dudes on this forum that know that just having cool rifles do not a DM make.
Renegade0100
05-12-19, 09:32
As a Squad DM, he will spend as much time kicking doors as anyone. If the DM always stays out on overwatch he might as well be in Weapons with the 240s that always stay out.
I don't see much juice being squeezed going from 16" to 20", and I'd prefer not to kick doors with a 20". I also think the Recce is the original DMR, and got it pretty right.
Then I suppose that settles it- 16 inches. Thanks for everyone's input.
Boba Fett v2
05-12-19, 14:12
A week is nothing compared to what it should be. My division's new marksmanship course was two weeks and did that still didn't feel long enough.
Yup. Like when they forced all non-infantry types to go through a few days of MOUT. Now you're trained to clear rooms like CAG. Get after it!
Thankfully our scout platoon recognized the flawed check-the-block training for what it was and the PL and I ensured we drilled the shit out of what we needed to do to ad nauseam during our downtime, every chance we got. My guys probably wished me dead for it initially, but when we found ourselves frequently forgoing our traditional reconnaissance mission, going to house to house and fighting from the streets to the rooftops... I'll just say sweat saves blood.
Um... What the hell were we talking about?
As a Squad DM, he will spend as much time kicking doors as anyone. If the DM always stays out on overwatch he might as well be in Weapons with the 240s that always stay out.
I don't see much juice being squeezed going from 16" to 20", and I'd prefer not to kick doors with a 20". I also think the Recce is the original DMR, and got it pretty right.
This was basically my experience - the only improvement having LPVO hardware offered is that when the guy with a Mk12 was posted to overwatch with a 240, he had better glass. That was 90% of the improvement, and the other 10% was having something with a can at all.
The actual concept of precision rifle weapons is one that requires a lot of comparatively affordable software improvements and significant range time before the hardware is going to be the limitation. The whole idea of 'that should go in an SRB' is just a side effect of how bass-ackwards the entire notion of professional skillsets are handled in any military unit.
It's worse as the most POGue flavored unit out there being somebody who can actually shoot, because the grunts we were attached to were always confused why I lived in an air conditioned tent after I'd go to the range with them, because I had made myself an at least mediocre shot with SDM skillset in my own spare time.
This was basically my experience - the only improvement having LPVO hardware offered is that when the guy with a Mk12 was posted to overwatch with a 240, he had better glass. That was 90% of the improvement, and the other 10% was having something with a can at all.
The actual concept of precision rifle weapons is one that requires a lot of comparatively affordable software improvements and significant range time before the hardware is going to be the limitation. The whole idea of 'that should go in an SRB' is just a side effect of how bass-ackwards the entire notion of professional skillsets are handled in any military unit.
It's worse as the most POGue flavored unit out there being somebody who can actually shoot, because the grunts we were attached to were always confused why I lived in an air conditioned tent after I'd go to the range with them, because I had made myself an at least mediocre shot with SDM skillset in my own spare time.
What’re you getting at with the SRB comment? You don’t think it should be listed?
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ViniVidivici
05-13-19, 11:50
Does anybody here think that LPVOs will become the new standard for MK12/SPR/SDM type rifles, or will a 3-10ish type traditional scope always be what seems best for these?
Didn’t they already buy Sig 1-6x optics?
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Renegade0100
05-13-19, 11:58
Does anybody here think that LPVOs will become the new standard for MK12/SPR/SDM type rifles, or will a 3-10ish type traditional scope always be what seems best for these?
I think it makes more sense to use an LPVO, especially in the near future as 1-10x’s become more common and viable.
Didn’t they already buy Sig 1-6x optics?
For the new Army SDM rifle, yup. And I foresee LPVOs being the standard in the role across the DoD with the quality and attributes of modern LPVOs.
Also, vinividivici, 3-10x optics were not really the standard before, at least for the Army. ACOGs were commonly on SDM rifles too. It was a real smattering of optics because the role is not MTOE and units use what they have on hand or buy outside of the regular channel.
indianalex01
05-13-19, 22:30
If we could issue an entirely new set of rifles to the U.S. military right now (or it could be for contractors, or even just a squad of dudes), what would be the ideal setup and combination? I'm using my personal build as an example of something I think is an ideal setup for a large array of situations; if I were in control of determining what gets issued to everybody, I would choose something similar to the above build. What would be the DMR equivalent?
We know that the military takes awhile to catch up on civilian trends; innovations and improvements hit our markets years before it gets picked up by Uncle Sam- see the recent adoption of the new URGI Geissele uppers as an example (adopted last year- we've had that stuff for quite a bit prior).
I'm discussing the ideal combination, barrel lengths, and setups for a carbine and DMR to be used in a squad taking into account the quality, modern gear available on the market. Again, this is all hypothetical.
I would say a Colt 6960 with a better trigger. 1-6x optic with BDC and illuminate reticule. I have found BCM barrels to be inaccurate. BCM doesn’t even have an Accuracy standard and wouldn’t replace the barrel. Couldn’t hold 5inch at 100 withFGMM.
indianalex01
05-13-19, 22:35
Considering how anemic 5.56 can get at range, wouldn't you want the most velocity that you can reasonably get? 20" doesn't /seem/ too long to me, given that the M16 was our service rifle since Vietnam. Is the shortened length that you get with the 16" justified over the loss in velocity you get when going below 18" or 20" for a DMR role?
The Round rounds are more effective now. Take for example the M318 SOST round. Rounds like this equalize shorter barrels and do damage at longer range. Fusion, T3 and many others do major damage at longer ranges. I love 20 inch but no need.
The Round rounds are more effective now. Take for example the M318 SOST round. Rounds like this equalize shorter barrels and do damage at longer range. Fusion, T3 and many others do major damage at longer ranges. I love 20 inch but no need.
Fusion and similar rounds cannot be used by our military.
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indianalex01
05-13-19, 22:47
Fusion and similar rounds cannot be used by our military.
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Mk318, M262 and M855A1 can. No need for a 20’ anymore.
Mk318, M262 and M855A1 can. No need for a 20’ anymore.
Muzzle velocity isn’t everything. Bullet selection is key. M262 is the way to go. The 318 has a terrible BC and is transonic at around 550 yards and has 130 FPE. It’s a 200 yard round.
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indianalex01
05-13-19, 23:28
Muzzle velocity isn’t everything. Bullet selection is key. M262 is the way to go. The 318 has a terrible BC and is transonic at around 550 yards and has 130 FPE. It’s a 200 yard round.
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The SOST 318 Mod 1 has a better BC then the Mod 0. I was speaking from a damage point of view. It’s much better then 262 and is barrier blind. Better for glass and car doors. 262 will be a alittle more accurate for sure.
The SOST 318 Mod 1 has a better BC then the Mod 0. I was speaking from a damage point of view. It’s much better then 262 and is barrier blind. Better for glass and car doors. 262 will be a alittle more accurate for sure.
Yeah but from a DMR perspective, the 318 just doesn’t ever get there ;)
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Deadsquiggles
06-07-19, 07:38
I’d say essentially the new URGI but with a 16” barrel and a 2.5-10x scope. 16” is fine as proved by the Mk12 Mod H and the handguard would be up to date.
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