View Full Version : Cold hammer forged barrels
Other than HK & Diemaco(Colt Canada) who makes cold hammer forged barrels for AR's?
Doesn't Lothar Waltham?
HTH,
Sean
K.L. Davis
08-18-06, 00:12
Lothar Walther uses button rifling.
Their barrels are made with an "in house" steel called LW50... they are very nice barrels, catering to target shooters, prices are really pretty good for what you are getting, a long tube with mathed bolt and extension runs close to 400 beans iirc.
Other than HK & Diemaco(Colt Canada) who makes cold hammer forged barrels for AR's?
Those are the only ones I'm aware of, however, I do know of another company trying to get ramped up for this. Don't expect anything anytime soon, however.
What exactly are the advantages of a cold hammer forged barrel?
Keeping it to chrome lined barrels, would it be much better than a quality barrel such as the ones made by BCM?
Sorry. For some reason, I thought I'd read that they did hammer forged bbls too.
Here's their site: http://www.lothar-walther.de/html/249.php
No mention of CHF bbls though. I spelled the name wrong too. Sorry for the confusion.
Sean
K.L. Davis
08-18-06, 10:01
17-4 ya say? :o
No, I said "some say" that it is doped 17-4, or a 630 with some stuff added to it.
I dont think it is, at least I am told that it is not a precipitation hardened steel and therefore does not have these issues of overheating that 17-4 does.
LWRC is now making Cold Hammer Forged Barrels. They are also using a new coating process on their steel that is more rugged and more scratch resistant than chrome lining. They make Awesome rifles, their customer service is bar none, but the demand outweighs their supply. Good things come to those who wait.
MikeCLeonard
10-20-08, 23:37
Noveske
Noveske has some and I will be getting some 16in mid gas systems and some 12.5in barrels.
Robb Jensen
10-21-08, 04:57
I'll have to double check but IIRC FN barrels are hammer forged.
I'll have to double check but IIRC FN barrels are hammer forged.
That is my understanding, as well.
I know SIG was originally planning to use FN as the vendor for 556 barrels in part because they would be hammer forged.
LWRC is now making Cold Hammer Forged Barrels. They are also using a new coating process on their steel that is more rugged and more scratch resistant than chrome lining. They make Awesome rifles, their customer service is bar none, but the demand outweighs their supply. Good things come to those who wait.
Post #1 eh?
Are you guys at Leitner Weiss at least posting this stuff from computers outside of the business these days?
rightwingmaniac
10-21-08, 21:59
my lwrc 6.8 m6a2 srt came with a chf barrel with no chrome lining. and no i dont work for them. i have the 14.5 w/ a p/a flash hider. its one bad motha. i own 4 ar's and its my fav. so far. yes that includes a colt 6920, lmt mrp, and pof.
The ironic thing is that several Fudd rifle companies were using CHF barrels nearly four decades ago. Back in February 1971, "American Rifleman" ran the second of a three-part article by Jac Weller on the construction techniques used by US firearm manufacturers. Remington, Ruger, Weatherby, and Winchester were all cited as using CHF barrels for at least some calibers and models.
According to Roy Weatherby's biography, he was using CHF barrels in his Mark V rifles as early as 1959. (They were made by Sauer at the time.)
I'm not sold on cold hammer forging. I still don't know what effect it has on accuracy and velocity. Those are the two most important metrics, for me.
A friend woke me this morning to tell me that his new SR15E3 is a 3 minute gun.
And I've been told that LW50 is 410 stainless, although I've never talked to them about it.
Just because a company sells a weapon with a hammer forged barrel does not mean the blank was manufactured in house. Keep that in mind.
Stretz Tactical Inc
10-22-08, 18:13
LWRC is now making Cold Hammer Forged Barrels. They are also using a new coating process on their steel that is more rugged and more scratch resistant than chrome lining. They make Awesome rifles, their customer service is bar none, but the demand outweighs their supply. Good things come to those who wait.
I like their products, but their customer service is nothing but excuses and unreturned phone calls.
That is my understanding, as well.
I know SIG was originally planning to use FN as the vendor for 556 barrels in part because they would be hammer forged.
So are FN barrels hammer forged?
service is nothing but excuses and unreturned phone calls.
Like so many of my dates;)
Gutshot John
10-22-08, 20:52
Good Article on Hammer Forginng.
http://technology.calumet.purdue.edu/met/higley/Precision%20Shooting%20Magazine%20-%20November-%202005%20(Vol_%2053%20-%20No_%207).htm
Good Article on Hammer Forginng.
http://technology.calumet.purdue.edu/met/higley/Precision%20Shooting%20Magazine%20-%20November-%202005%20(Vol_%2053%20-%20No_%207).htm
Thank you for that link, it was very interesting.
sniperfrog
10-23-08, 18:54
Good Article on Hammer Forginng.
http://technology.calumet.purdue.edu/met/higley/Precision%20Shooting%20Magazine%20-%20November-%202005%20(Vol_%2053%20-%20No_%207).htm
That article in Precision Shooting about hammer forged barrels has a part two where they did some accuracy testing. They took some Ruger factory hammer forged barrels and set them up for an AR. They shot under a minute consistently with several types of ammo and some groups were in the half minute range. Not bad for $60 barrel blanks.
Gutshot John
10-23-08, 19:06
IIRC hammer forging is the way they do polygonal rifling. Supposedly slightly more accurate and higher velocities, but that's just what "they" say.
Yeah the blank is only $60, but the machine is $20 million. You have to make A LOT of barrels to make that one come out.
wild_wild_wes
10-25-08, 00:31
Noveske
Noveske barrels are hammer forged?
Wow, I thought that was a great article. I knew the basic principle of pounding the blank around a mandrel but never knew what really went into it. Thanks!
-Jesse
Noveske barrels are hammer forged?
they don't advertise it, but yes. i think stick makers are hesitant to shout it out on street corners till it gets a little more mainstreamed.
wild_wild_wes
10-25-08, 15:32
Wow. I was under the impression that hammer-forged barrels in general were not very accurate.
Robb Jensen
10-25-08, 16:52
Wow. I was under the impression that hammer-forged barrels in general were not very accurate.
The HK PSG-1 has a hammer forged barrel with polygonal twist and is considered by many to be one of the most accurate semi auto rifles in the world.
Colt Canada, FN, Hk, KAC (for some) and several others do CHF barrels.
They are superior serivce rifle and MG barrels. In my experiences they are not as accurate over distance as SS barrels can be.
The PSG-1 is accurate - but I would suggest nothing a Mk11 or custom barrelled AR10 could not do, and Hk would not charge $8,500 to rebarrel it for your unit...;)
Robb Jensen
10-25-08, 17:29
Colt Canada, FN, Hk, KAC (for some) and several others do CHF barrels.
They are superior serivce rifle and MG barrels. In my experiences they are not as accurate over distance as SS barrels can be.
The PSG-1 is accurate - but I would suggest nothing a Mk11 or custom barrelled AR10 could not do, and Hk would not charge $8,500 to rebarrel it for your unit...;)
Yes I've found that out too. I've fired 2 different PSG-1s a few hundred rounds through both out to 500 meters in the late 80's at Quantico (that 6x scope leaves a lot to be desired). The PSG-1 is a very dated design now. I agree that the .308 AR platform is just as accurate if not more accurate for a whole lot less money. I too find SS barrels more accurate than most other barrels but have roughly 1/2 the serviceable life as other barrels.
True true -- I was just hassling you - and still bitter over Hk's rebarrel fees from years gone by.
sideshowbob
10-25-08, 18:09
I like their (LWRC) products, but their customer service is nothing but excuses and unreturned phone calls.
I am going to have to agree with KCS on this one. I just received my rifle I ordered in February. Notwithstanding the long wait, they also shipped me the wrong gun. It was quite frustrating to say the least.
They could sell so many more rifles if they just got their act together.
Razorhunter
10-25-08, 18:14
So what exactly IS the advantage of a CHF bbl???
Also, are you guys saying that Colt Canada (Diemaco) does offer CHF, but COLT USA does not?? (IOW's, the Colt 6920's, etc, sold here in the US do not have CHF, but Canadian/Diemaco bbls do??)
What is the advantage to CHF bbls???
Finally, what about BCM bbls? I assume they do NOT have CH Forging??
So are FN barrels hammer forged?
Not on the AR-15s they make.
More hammer forged barrels are produced in the workd than by any other method. Virtually all pistol barrels are hammer forged. Why? While initial equipment/mandrel/hammer cost is very very high, it is so fast and QC is so easy that in mass production, per unit costs are much much lower than any other manufacturing method.
Besides cost, the hammer-forging process work-hardens the inside barrel creating a harder and tougher barrel without making it much more brittle. A big plus indeed. hammer forging also changes the crystalline structure of entire barrel, making to tougher.
The downside is that, compared to button or cut barrels, induced manufacturing stresses are horrendous, and must be relieved, usually by heat, and sometimes with cryo. failure to properly stress-relieve will hurt accuracy. Always. Most production rifles do not have fully stress-relieved barrels, just partial, to save cost. That's why your Remington barrel "walks" shots as it warms up.
Another downside of hammer forging is that the high equipment costs mean that you are stuck with what the product that the manufacturer is geared up to make, whereas a button or cut-rifling maker can switch tooling easily to make custom barrels easily.
If you own a rifle by Colt, Remington, Winchester, Ruger, Marlin, Sako, Savage, almost any European brand, or a pistol of any brand, you own a hammer-forge barrel. It probably is working fine for you.
Robb Jensen
10-25-08, 19:48
Not on the AR-15s they make.
FN makes AR-15s?
Last I checked AR15/AR-15 was a Colt patented name thing.
I know FN makes M16A2s, M16A3s and M16A4s as well as most of the belt feds used by the US Military.........and I have a few friends employed by FNH.
Aren't the vast majority of AK barrels hammer forged?
wild_wild_wes
10-25-08, 20:18
In my experiences they are not as accurate over distance as SS barrels can be.
What about hammer-forged stainless steel barrels? Like Noveske?
Heavy Metal
10-25-08, 20:43
Aren't the vast majority of AK barrels hammer forged?
Yes, and so was the chocolate chip cookie I just eated...........
Well AK barrels are anyways.
If you own a rifle by Colt,
Nope - drop forged.
What about hammer-forged stainless steel barrels? Like Noveske?
Only the N4 barrels are hammer forged, the stainless barrels are button rifled.
Post #1 eh?
Are you guys at Leitner Weiss at least posting this stuff from computers outside of the business these days?
I don't work for LWRC either, but I will vouch that their products and customer service are awesome. I got one of their older model M6 rifles and their quality are awesome. I would like to get one of their new M6 A2s with the new coating. They don't chrome line their barrels anymore, they use a new process that is supposedly alot stronger and longer lasting than Chrome lined barrels. They take great pride and attention to detail in their work. I would highly recommend their products.
Just because a company sells a weapon with a hammer forged barrel does not mean the blank was manufactured in house. Keep that in mind.
LWRC does all of their own work in house, they may not use their own blanks, as they aren't a steel manufacturer, but they do use top grade materials to do their work on.
I like their products, but their customer service is nothing but excuses and unreturned phone calls.
The best way to contact them is on their websight forum or via e-mail. They are very busy with order filling and they are trying to expand their operation. If they get their contract for making the M6A3 (open bolt, closed bolt machine gun) they will have the funds and the resources to keep up with the demand for their products. I will admit that 14 weeks or longer is a long time to wait for their products, but it is worth the wait. You can also find their rifles for sale on auction sights like gunbroker and also on their for sale section on their forum.
Kowboy.... you're kidding, right? You're about as obvious as the wife from The Truman Show. Does your hat say "Paid Endorsement" by any chance?
Kowboy.... you're kidding, right? You're about as obvious as the wife from The Truman Show. Does your hat say "Paid Endorsement" by any chance?
No, I am on LWRC's forum, but I AM IN NO WAY affiliated with LWRC except for the fact that I have one of their rifles and can vouch for their quality. I guess they Should pay me since I do brag about their products so much. Sorry if I got off topic or was sounding like I was hanging off LWRC's nuts, but I thought I'd just point out another manufacturer who makes Cold Hammer Forged Barrels, but I digress....
Robb Jensen
10-28-08, 05:23
I saw 3 LWRC rifles last week through the shop on transfer. They look a lot better than they did earlier. I couldn't make out the manufacturer of the new barrels, they appear to be IonBonded.
Regarding LWRC barrels, I copied this from the LWRC Forums:
Post Ferritic Nitrocarburizing Information
The standard M6 barrel features a ferritic salt bath nitro carburized interior and exterior finish. This finishing process is also applied to the barrel extension and gas port. This finishing process is a surface conversion process in place of industrial hard chrome and is therefore inherently free from nodules, flaking, pits, stripping, or anode burrs. The process results in chemical and structural composition changes that can be described as a case hardening to a depth of 0.005” of the alloy leading to increased surface hardness, lower coefficient of friction, enhanced surface lubricity, improved running wear performance, increased sliding wear resistance, enhanced corrosion resistance and heat resistance over industrial hard chrome. Since the process is a surface conversion and does not add material to the internal dimension of the bore, the barrels can be hammer forged on size over a very precise polished rifle mandrel. With hard chrome, the bore must be manufactured oversized or honed and electro-polished to make the interior dimension oversized making room for the chrome plating. This plating is inconsistent which is the reason sniper or target barrels are typically not chromed. Nitrocarburizing has proven superior as a surface finish to phosphating to oxidization when subjected to MIL-STD-810f salt fog/spray testing and is a scratch resistant flat black finish.
In addition the barrel extension and gas port are also surface converted minimizing barrel extension wear, increasing corrosion resistance and limiting gas port erosion. Cross sectional analysis done by HP White Laboratories before and after nitro carburizing proved the surface conversion process does not negatively interfere with the heat treat or temper of the barrel extension. LWRCI contracted HP White to conduct these tests.
The ferritic salt bath nitro carburizing process has been proven by independent testing to be superior to chromium plating both it terms of corrosion resistance and abrasion resistance, lubricity and wear. It has been long adopted by FAMAE of Chile for use in all government small arms, and also by the Polish Military. It has been adopted by Sig Arms for use in their carbines, Glock in their pistol bores and various other large military arms manufacturers with excellent results.
Now I certainly hope that nobody thinks I work for LWRC ;)
theJanitor
10-28-08, 18:40
i always wondered why my stainless heavy barreled 10/22 looked the way it does
Stretz Tactical Inc
10-29-08, 11:28
I am going to have to agree with KCS on this one. I just received my rifle I ordered in February. Notwithstanding the long wait, they also shipped me the wrong gun. It was quite frustrating to say the least.
They could sell so many more rifles if they just got their act together.
I ordered mine in February also. It will be here on Friday. There customer service reps. make up excuses and stall and everytime you call, they add you to the "priority ship list". I guess they must have forgotten that they added you the last few times you called. The people on their forum are also obnoxious immature assholes - like some of the people on AR15.com.
Did they at least get you the right gun, right away or did you have to wait a while? There are other people on their forum who wrote about ordering an upper and not getting the buffer and spring, other people had minor complaints like the bottle of oil that is supposed to come with the gun, didn't. People had parts break, etc. They also promised to ship all the M6A2's with magpul back up sights to make up for the long wait and then that post convieniently disappeared.
LWRC does all of their own work in house
While they may have plans to eventually do all of their own work in house, they do NOT currently manufacture all of their rifle parts.
As for hammer forged barrels, I still believe HK makes the finest ones available. They do get their steel from an outside vendor, as NickB mentioned, and it's damn tough stuff.
Tspeis
While they may have plans to eventually do all of their own work in house, they do NOT currently manufacture all of their rifle parts.
As for hammer forged barrels, I still believe HK makes the finest ones available. They do get their steel from an outside vendor, as NickB mentioned, and it's damn tough stuff.
Tspeis
LWRC does not have plans to make all parts in house. Not even Colt or FN do that, but they are bringing a lot of the critical processes in house. They have purchased several turning centers that will allow them to profile their own barrels and make the piston parts and bolts. With the Matech merger, they are also ISO9001 compliant (soon to be certified) and will be following the TDB for all aplicable parts. They are currently one of three manufacturers that made the phase two downselect for the Marine Corps IAR Program. Their carbines have been adopted by several domestic LE/gov agencies as well as several foreign military units.
I don't know who is making their barrels for them now, but they are the best barrel currently available in a combat weapon. The combination of the hammer forging process and SBN interior/exterior finish makes for an exceptionally strong, accurate barrel. I shot "High Shooter" with one of the new guns at a recent Pat Rogers course without a single malfunction or stoppage (~1700 rounds over 3 days).
I don't work for LWRC, but I do heavily endorse their products. I also consider several of the staff to be my friends.
Stephen
Doesn't Lothar Waltham?
HTH,
Sean
No.
C4
I'll have to double check but IIRC FN barrels are hammer forged.
Correct Sir.
C4
I'm not sold on cold hammer forging. I still don't know what effect it has on accuracy and velocity. Those are the two most important metrics, for me.
A friend woke me this morning to tell me that his new SR15E3 is a 3 minute gun.
And I've been told that LW50 is 410 stainless, although I've never talked to them about it.
There are 5 things that define accuracy in an AR. They are:
1. Quality Barrel
2. Quality Ammo
3. Quality Trigger
4. Quality Optic
5. Quality Shooter
The SR15 has two of the five. Did your friend fill in the other gaps?
C4
Noveske barrels are hammer forged?
Their N4's are.
Every N4 barrel we have tested shoots under 1MOA. I have seen very few chrome lined barrels match this.
C4
FN makes AR-15s?
Last I checked AR15/AR-15 was a Colt patented name thing.
I know FN makes M16A2s, M16A3s and M16A4s as well as most of the belt feds used by the US Military.........and I have a few friends employed by FNH.
You know what I meant.
rightwingmaniac
11-13-08, 01:54
i am also on the lwrc bandwagon. their shit is top notch. i have a m6a2 6.8 srt with a 14.5" barrel and a p/a flash hider. took it out to the range this weekend with my trijicon nsn. had groups just over 1" @ 100yards. im sold on the barrel. top quality all the way.
Aren't the vast majority of AK barrels hammer forged?
Yes, cold hammer forging, i.e. "the Steyr process", is an excellent way to make a lot of high quality, very consistant barrels.
When done on an industrial level, you can turn out a bunch of barrels quickly, all nearly identical. The machine itself is expensive, which is why you don't see anyone but the big boys doing them.
FYI I have had both C7 and C8SFW barrels - neither freefloated, put 5rds of C77ball inside a 1" patch @ 100m on multiple times (96-'02 ammo lots)
However when we benched my 16" KAC gun compared to a 16" SFW and 20" C7A2 - the SS Douglas barrel with wylde chamber was under .33 and the others where surfing the MOA zone.
Their N4's are.
Every N4 barrel we have tested shoots under 1MOA. I have seen very few chrome lined barrels match this.
C4
1) What type of ammo do you use in your testing?
2) Up to what distance do you get sub-MOA?
3) Are the Noveske barrels you carry the N4?
Thanks.
1) What type of ammo do you use in your testing?
2) Up to what distance do you get sub-MOA?
3) Are the Noveske barrels you carry the N4?
Thanks.
1. BH's Blue Box 69-77gr
2. 100yds and 1.5" groups out to 200yds
3. We stock both the N4 and SS barrels
C4
1. BH's Blue Box 69-77gr
2. 100yds and 1.5" groups out to 200yds
3. We stock both the N4 and SS barrels
C4
PM sent.
vicious_cb
11-14-08, 18:12
Noveske barrels were tested by molon over on arfcom
For the N4 16" recce barrel using 10 shot groups and handloaded ammo and taking the average of 8 groups it came out to about 1.25 MOA.
Sub-MOA N4 barrels are not. The stainless steel recon barrels are very capable of sub-MOA
http://www.ar15.com/forums/topic.html?b=3&f=118&t=401613
Noveske barrels were tested by molon over on arfcom
For the N4 16" recce barrel using 10 shot groups and handloaded ammo and taking the average of 8 groups it came out to about 1.25 MOA.
Sub-MOA N4 barrels are not. The stainless steel recon barrels are very capable of sub-MOA
http://www.ar15.com/forums/topic.html?b=3&f=118&t=401613
Thanks for the thread - very interesting. Molon does good work! :)
Noveske barrels were tested by molon over on arfcom
For the N4 16" recce barrel using 10 shot groups and handloaded ammo and taking the average of 8 groups it came out to about 1.25 MOA.
Sub-MOA N4 barrels are not. The stainless steel recon barrels are very capable of sub-MOA
http://www.ar15.com/forums/topic.html?b=3&f=118&t=401613
His barrel was a statistical sampling of ONE. He also used hand loaded ammo in one grain weight.
The worst groups I saw were with 77gr MK's.
C4
vicious_cb
11-16-08, 03:37
His barrel was a statistical sampling of ONE. He also used hand loaded ammo in one grain weight.
The worst groups I saw were with 77gr MK's.
C4
Yeah but notice how he used it as a control load for BOTH the N4 and stainless recon barrel. The recon barrel shot more than .25 moa tighter with the same ammo. So wouldnt the performance difference be roughly the same if he used different ammo out of both barrels?
That one particular stainless barrel may simply have been better mated to that particular load. He could easily find another load (commercial ammo or hand loaded) that shot better in the other barrel instead.
Yeah but notice how he used it as a control load for BOTH the N4 and stainless recon barrel. The recon barrel shot more than .25 moa tighter with the same ammo. So wouldnt the performance difference be roughly the same if he used different ammo out of both barrels?
No. I have had SS Noveske barrels that DID NOT shoot 1MOA. Sampling of one means zero.
I test fire (for accuracy) TONS of Noveske N4's. They all perform between .75-1MOA.
C4
vicious_cb
11-16-08, 19:47
No. I have had SS Noveske barrels that DID NOT shoot 1MOA. Sampling of one means zero.
I test fire (for accuracy) TONS of Noveske N4's. They all perform between .75-1MOA.
C4
Well you havent told us your methodology yet. 3,5,10-shot groups? At what range? What was your testing set up? Ammo used? How many groups did you fire? Did you take an average of the groups?
That one particular stainless barrel may simply have been better mated to that particular load. He could easily find another load (commercial ammo or hand loaded) that shot better in the other barrel instead.
Can you really find a load out there that impartial to both barrels? It was a control load thats all. The control is meant to be as non-biased as possible or it would skew your results. That being said do you think 69gr handloads would have been a better control? Would it have been less impartial to both barrels than the 77gr SMK?
vicious -- That's just it. No single load can tell the whole story. It's certainly more convenient (I use just one myself for tracking the accuracy on my M&P endurance test gun) but if you want to compare multiple guns, you have to use multiple loads.
Also, if I recall correctly, you said he was using 10-shot groups. That's well and good for the purposes of his own test, but it makes it impossible to compare to other people's results since 5-shot groups are the generally accepted norm. Since additional shots can only enlarge a group and not shrink it(*), a 10-shot group is likely to be larger than a 5-shot group. This is particularly important in this case because (presumably -- someone correct me if I'm wrong) when folks talk about an MOA gun, they mean a gun that shoots within one minute of angle for a five shot group.
* this assumes we're talking about measuring Extreme Spread, which is the norm for almost every group you see discussed online; if you're using Mean Average Radius then of course you can improve your group by shooting more rounds that are closer to the center point than the previous MAR ...
vicious_cb
11-16-08, 21:32
vicious -- That's just it. No single load can tell the whole story. It's certainly more convenient (I use just one myself for tracking the accuracy on my M&P endurance test gun) but if you want to compare multiple guns, you have to use multiple loads.
Also, if I recall correctly, you said he was using 10-shot groups. That's well and good for the purposes of his own test, but it makes it impossible to compare to other people's results since 5-shot groups are the generally accepted norm. Since additional shots can only enlarge a group and not shrink it(*), a 10-shot group is likely to be larger than a 5-shot group. This is particularly important in this case because (presumably -- someone correct me if I'm wrong) when folks talk about an MOA gun, they mean a gun that shoots within one minute of angle for a five shot group.
* this assumes we're talking about measuring Extreme Spread, which is the norm for almost every group you see discussed online; if you're using Mean Average Radius then of course you can improve your group by shooting more rounds that are closer to the center point than the previous MAR ...
Its basic statistics, 5-shot groups just dont tell the whole story. The larger the sample size the closer you get to the "real" group size. Ive shot .5-.75" 5-shot groups occasionally. but does that mean my gun is sub-moa? No it does not, my gun is actually closer to ~1 moa which Ive found by saving all my targets from the past couple of months using 10-shot groups and measuring the extreme spread
Rick Jamison, the author of the Precision Reloading column in Shooting Times magazine approaches accuracy testing in a very scientific manner. He uses a machine rest for testing and fires 10-shot groups. Here are his own words on the subject from one of his articles:
There are stories of a single bullet that for no explained reason flies out of what might have been a tight cluster. This often occurs with a three-shot string and many times with a five-shot string. If you're lucky enough to fire a group without a flier, you can end up with a very tight group. However, usually what happens if another five or seven shots are fired to complete a 10-shot string, other bullets fill in the space between the main group and the flier to make a reasonably rounded group. Ten shots are a more reliable indicator when it comes to predicting what a load is likely to do in the future.
The problem with 10-shot groups is that when you report them, everyone thinks you aren't shooting very well or that the ammunition is not good because the group sizes are so much larger than three- or five-shot groups. Also, when we're firing three- or five-shot groups with a flier, it is only natural to assume that it was caused by a flinch or "pulling" the shot. Therefore, since the flier was our own fault, the tendency is to eliminate it from any reporting of group size.
This is one of the advantages of using a machine rest... The machine rest reduces the human element.
After using this machine rest for several years, I have determined that a 1.5-inch 10-shot group at 100 yards... is a good one.
http://www.ar15.com/forums/topic.html?b=3&f=118&t=279218
10 shot groups are better - but then again so would be 20 or 30...
I use 10 rd groups when shooting for group size -- but to zero I use 3 - why to save ammo, and sometimes I even use 1.
My Jerry Rice built Remington 700 .308 gun would toss 10rds into a very easy 1 ragged hole group around .24-.32 if I did my thing @ 100m. Sample size one - however Jerry builts great guns.
Really the theory on sample size requires N to be greater or equal to 32 to make a statistically valid test.
One barrel is an idea - the same with one load.
Neil (newarguy) on ARF.com did a 6.8 shoot last year - it was interesting - but it was a test of one gun from several manufacturers - so it really did not do much than tell you how one gun shot several hundred round of 6.8 versus a few other one gun samples.
The methodology of the test is key to this discussion as well.
100m or 100yd's
# of round
temp / wind / light
positions/support
single fed or mag loaded (and this can make a difference)
ammo
TIME - did the bbl cool back to baseline between rounds
Well you havent told us your methodology yet. 3,5,10-shot groups? At what range? What was your testing set up? Ammo used? How many groups did you fire? Did you take an average of the groups?
Actually I gave some info already. I shoot 4 groups of 5rds and then average them out. Ammo used is everything from BH 69gr-77gr and BH MK262. Distances fired range between 100yds to 200yds. I also load each round by hand into the chamber.
C4
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