View Full Version : Can't get new barrel to group.
When shooting bolt rifle I'll shoot .4's-.6's 7 shot groups. Re-barreled my "SPR" with a Compass Lake barrel. Shooting reloads (LC bras, Win primers, 8208 XBR, 77smk at 2.250) that are better than what I would suspect from a semi platform. SD are 9-10 ES 20 which to me is good and with a average velocity of 2750. total round count now is 120. First 20 or so rounds I stopped to clean the free-bore/throat area to rid of copper. Barrel was tq multiple times to seat the new barrel nut at 40ft/lbs and I did use Aero-shell grease. Muzzle device was tq to 20ft/lbs and used rockset. Trigger is a SSA too. Upper and lower are BCM and I can fit 0.003-4 feeler gauge in between the upper and lower.
Shooting prone and using a rear bag at 100 yards I get groups of 1-1.5 moa. To be fair I have not shot semi in a while but when I did I got 1/2 - 3/4 moa. I was taught how to shoot a bolt gun, but not a semi. I often hear you have to "drive it" different. What that differences is? I do not know. So it could be me but I honestly doubt it as I record where the crosshairs were when the trigger broke.
I'm starting to through the list of diagnosing. First going to take the brake off (AAC Brakeout) and make sure it wasn't that causing the issue. I may load up some more ammo and do a seating depth test, however I've never seen a group that shoots 1.5-2 moa shrink alot. I don't think the barrel needs to be "broken in" but I'm honestly going clueless.
Yes at the end of the day it could be me. I shoot alot more bolt guns and AR have to be driven different at least that's what I'm told. I don't know what the difference is but I did shoot consistent 1/2-3/4 on my old setup. So that has to account for something.
Long Range Trigger Monkey
01-01-16, 18:16
Definitely try the muzzle device first. Last year I about drove myself batsh*t crazy about four weeks before a DMR championship match because my rifle suddenly went from a 3/4 MOA gun to something more akin to a shotgun. I tried everything, I even went so far as to buy a new barrel, which seemed to help and got me through the match finishing in the top ten. However the one thing that I didn't check was the muzzle device because had I done that I would have noticed that there was damage at the front aperture on the inside edge. After I slapped a different muzzle device on there accuracy went back to sub-MOA with ease.
You might also want to try a couple different types factory match ammunition also, some barrels like certain kinds of ammunition. My DMR has a 1:8 barrel so in theory it should shoot 69gr match and 77 gr match with relative ease but a friend let me try out 20 rounds of some new brand of 69 gr match ammo and it shot like hell. Tried some tried and true Razor Core 77gr match and groups were under an inch again.
Make sure all of your fasteners securing the scope are tight, I've had that rear its ugly head once before.
Do some dry fire before actually shooting to help get your mind focused and work on your follow through, the fundamentals are the same as shooting a bolt gun.
Good luck!
When going with a new barrel, I typically like to start with factory ammunition to get a benchmark. I typically go Federal and Black Hills. In the case of 5.56 I usually go with 69gr and 77gr. I also try grouping off the bench with a solid rest (Sinclair bR) and rear bag. I then go prone while loading the bipod pretty heavily. I had a JP rifle that grouped much better off the bipod than the bag....
That said, your load data looks good for the 77gr but your barrel might not like that particular velocity. I would start with some load development after re-checking all your torque specs. This is the technique I use for working up new loads, if you don't have a technique you prefer already. When combined with a magneto speed, I can make quick work of the load development. http://optimalchargeweight.embarqspace.com/
The only mechanical thing I can think of is depending on the free float tube, sometimes the gas tube can make contact to one side of the receiver which can effect accuracy, though probably not that much.
Shooting the gas gun does require different technique than the bolt gun. I have found you have to treat the gas gun a little rougher and hold on more than you would with a bolt gun.
Good luck!
Djstorm100
01-01-16, 18:30
Tag for interest.
When going with a new barrel, I typically like to start with factory ammunition to get a benchmark. I typically go Federal and Black Hills. In the case of 5.56 I usually go with 69gr and 77gr. I also try grouping off the bench with a solid rest (Sinclair bR) and rear bag. I then go prone while loading the bipod pretty heavily. I had a JP rifle that grouped much better off the bipod than the bag....
That said, your load data looks good for the 77gr but your barrel might not like that particular velocity. I would start with some load development after re-checking all your torque specs. This is the technique I use for working up new loads, if you don't have a technique you prefer already. When combined with a magneto speed, I can make quick work of the load development. http://optimalchargeweight.embarqspace.com/
The only mechanical thing I can think of is depending on the free float tube, sometimes the gas tube can make contact to one side of the receiver which can effect accuracy, though probably not that much.
Shooting the gas gun does require different technique than the bolt gun. I have found you have to treat the gas gun a little rougher and hold on more than you would with a bolt gun.
Good luck!
Definitely try the muzzle device first. Last year I about drove myself batsh*t crazy about four weeks before a DMR championship match because my rifle suddenly went from a 3/4 MOA gun to something more akin to a shotgun. I tried everything, I even went so far as to buy a new barrel, which seemed to help and got me through the match finishing in the top ten. However the one thing that I didn't check was the muzzle device because had I done that I would have noticed that there was damage at the front aperture on the inside edge. After I slapped a different muzzle device on there accuracy went back to sub-MOA with ease.
You might also want to try a couple different types factory match ammunition also, some barrels like certain kinds of ammunition. My DMR has a 1:8 barrel so in theory it should shoot 69gr match and 77 gr match with relative ease but a friend let me try out 20 rounds of some new brand of 69 gr match ammo and it shot like hell. Tried some tried and true Razor Core 77gr match and groups were under an inch again.
Make sure all of your fasteners securing the scope are tight, I've had that rear its ugly head once before.
Do some dry fire before actually shooting to help get your mind focused and work on your follow through, the fundamentals are the same as shooting a bolt gun.
Good luck!
Thanks guys for the info.
How I do load development is a little odd but it works. I load up 5 rounds in .3 increments and fire those over a magnetospeed. With a free float handguard I can attach the magnetospeed to the rail and there fore shoot for groups and get velocity/SD/ES. 23.3 gave SD10 over 10 shot group 23.5 gave 9.6 and 23.7 gave the same as 23.5.
I did later switch to bushing neck die for my bolt guns that gave awesome results. I have RCBS dies, but here recently bought some Forster. I have not loaded up any using that die set yet. I do find forster/whidden/Redding to be higher quality than RCBS, personally.
Yes sir I've sired 75gr hornady match. Been trying to find some Federal 77 match but haven't be able to. Since of my trouble with the AAC cans and mounts, I wouldn't be surprise if something is messed up on the two Brake out's that I have. Barrel is 1:7 twist.
The scope mounts are good to go, I set the scope up at home and then again at the range. I use blue loc-tie on all the fasteners. I'm using a American defense mount.
I'm going to try it bare barrel, no muzzle brake.
You are right there on the load where I thought you would be. I havent chrono'd my load, but at 23.2 of XBR with the 77g SMK out of a compass lake spun Krieger 18" its a solid 1/2" gun. What barrel blank did you get from CLE?
My barrel took 150-200 rounds to break in. The first 50-60 were a bit erratic, but then it settled down nicely and really came together at around the 175 mark.
As far as shooting gas guns, 308 gas guns, yea they take a different technique. 223 gas guns(at least mine) I havent felt the need to "drive" the gun like I do with my 6.5 creedmoor gas gun(which is a pussy cat in its own right the way its setup) or the 308 LMT MWS(that ****ers a beast and requires attention).
You are right there on the load where I thought you would be. I havent chrono'd my load, but at 23.2 of XBR with the 77g SMK out of a compass lake spun Krieger 18" its a solid 1/2" gun. What barrel blank did you get from CLE?
My barrel took 150-200 rounds to break in. The first 50-60 were a bit erratic, but then it settled down nicely and really came together at around the 175 mark.
As far as shooting gas guns, 308 gas guns, yea they take a different technique. 223 gas guns(at least mine) I havent felt the need to "drive" the gun like I do with my 6.5 creedmoor gas gun(which is a pussy cat in its own right the way its setup) or the 308 LMT MWS(that ****ers a beast and requires attention).
Douglas. Maybe I don't have enough rounds down the tube and fouled enough. I've honestly cleaned it alot more than I should have thinking copper filled freebore was my issue.
I'm building a creedmoor semi now. Seems like I need to stop everything, take the muzzle brake off and work up a load. Starting at 23, 23.2, 23.4, 23.6,23.7. I typically do 7 shots per load for 1) if I screw up causing a flyer 2) even more data points. Get some brass size through forster die bumping the shoulder back .002 and maybe use BR-2 primers than the win.
Douglas. Maybe I don't have enough rounds down the tube and fouled enough. I've honestly cleaned it alot more than I should have thinking copper filled freebore was my issue.
I'm building a creedmoor semi now. Seems like I need to stop everything, take the muzzle brake off and work up a load. Starting at 23, 23.2, 23.4, 23.6,23.7. I typically do 7 shots per load for 1) if I screw up causing a flyer 2) even more data points. Get some brass size through forster die bumping the shoulder back .002 and maybe use BR-2 primers than the win.
stop cleaning the barrel. Ive cleaned mine once at 50rds. I think im at around the 500rd mark now and its still tight. If the groups open up, ill clean it.
I would pull your brake and see. You SHOULDNT need to redo your load just because you pull the brake off. If you do, throw the magnetospeed on, shoot 5, who cares about group size, you just want the lowest SD and ES you can get. That WILL shoot a good group when thats your goal. It will also be the most consistent out to distance too.
And for your gas gun you want to bump .004, bolt guns are .002. Hopefully the forster die you bought was a full length and not a bushing neck die.
stop cleaning the barrel. Ive cleaned mine once at 50rds. I think im at around the 500rd mark now and its still tight. If the groups open up, ill clean it.
I would pull your brake and see. You SHOULDNT need to redo your load just because you pull the brake off. If you do, throw the magnetospeed on, shoot 5, who cares about group size, you just want the lowest SD and ES you can get. That WILL shoot a good group when thats your goal. It will also be the most consistent out to distance too.
And for your gas gun you want to bump .004, bolt guns are .002. Hopefully the forster die you bought was a full length and not a bushing neck die.
It is a FL die. Redding and whidden do make FL dies that use bushing for the neck as well. With all the different brass I use bushing die makes no sense for my application.
I was cleaning the rifle per the instructions from Compass lake, that's all.
UPDATE
I took the brake off today and realized I had place .042 of shims and really had to put some effort to time the brake correctly. I then started over shimming the rifle and found that .037 worked fine with hand tightening bring it almost in place and only just a small amount of wrench force to bring the port to 12 o' clock. With rocksett it should not back out. I hope alot.
Kansaswoodguy
01-04-16, 00:03
Check your gas block has at least 1/8" clearance from handguard
Check your gas block has at least 1/8" clearance from handguard
I thought this may of been the issue but it appears not.
I'm going to call today to see what they can do. Either replace it with a standard chamber and move to a Kreiger or refund.
Did some testing yesterday with 4064 and have the same effect. All groups are 1.5-2 inches.
I thought maybe the gas block was hitting the rail, so I took the rail off. No marks at all
http://i1040.photobucket.com/albums/b409/Thisguy65/IMG_5641_zpsyz4ppqls.jpg
http://i1040.photobucket.com/albums/b409/Thisguy65/IMG_5648_zps5imj9azg.jpg
http://i1040.photobucket.com/albums/b409/Thisguy65/IMG_5647_zps7wf4putj.jpg
http://i1040.photobucket.com/albums/b409/Thisguy65/IMG_5654_zpsgczzu1vt.jpg
Some barrels require some break in followed by a thorough cleaning. Years ago, I purchased a Ruger heavy barrel .223 varmint rifle that should have been a tack driver, but shot 2-1/2" groups at 100 yards. I checked scope mounts, action screws, you name it and the rifle still grouped like a shotgun.
After roughly 150 frustrating rounds, I decided to trade off the rifle on something else. Before trading it off, I cleaned the bore thoroughly, then followed up with J.B. Bore Paste. After I cleaned the barrel, I decided to shoot another group before heading to the gun shop. The same ammunition shot 1/2 MOA out to 200 meters.
Kansaswoodguy
01-04-16, 21:27
Try taking the barrel nut off and check that the barrel extension fits snugly into the upper reciever. If not you can use Locktite to bed it in this can still be removed with use of a good quality heat gun if needed. Try a diffrent scope. Make sure everything is tight scope rings ect. Try a diffrent bolt maybe head space out of spec. Try black hills ammo or 55vmax 21gr imr 3031 CCI small rifle primer COL 2.25" this is my standard AR load if it won't shoot that, barrel has real issues. Did see a loose gas key causing issues once but it was causing cycling issues if I remember right. I also do not clean my barrels hardly ever unless the accuracy tails off then I will this takes hundreds if not thousands of rounds in most of my guns. I have a Bushmaster that has to have 40-60 rounds down the tube after a good copper cleaning to come back to shooting MOA. And I also have ruger m77 30-06 that looks like I've been copper mining after 5 rounds there all individuals.
I generally square and true the crown on all my AR's this can make a big difference.
C4
Sent from my iPhone using Tapatalk
Try taking the barrel nut off and check that the barrel extension fits snugly into the upper reciever. If not you can use Locktite to bed it in this can still be removed with use of a good quality heat gun if needed. Try a diffrent scope. Make sure everything is tight scope rings ect. Try a diffrent bolt maybe head space out of spec. Try black hills ammo or 55vmax 21gr imr 3031 CCI small rifle primer COL 2.25" this is my standard AR load if it won't shoot that, barrel has real issues. Did see a loose gas key causing issues once but it was causing cycling issues if I remember right. I also do not clean my barrels hardly ever unless the accuracy tails off then I will this takes hundreds if not thousands of rounds in most of my guns. I have a Bushmaster that has to have 40-60 rounds down the tube after a good copper cleaning to come back to shooting MOA. And I also have ruger m77 30-06 that looks like I've been copper mining after 5 rounds there all individuals.
Make sure the fit was snugged
Tired a different scope
Use blue loctie on the fasteners for the scope
Bolt was headspace just for that bolt
Tired Hornday match as well as a few other matc
BCG is fine
In spring of 2015, I bought a CLE DOUGLAS recon 16" barrel with 1:7, wylde chamber. It shot 2 MOA. I sent it back and they said that there was a burr in the gas port. I got it back and it still didn't group. They replaced the barrel and the new one shoots good.
I got a CLE DOUGLAS 20" 1:7, WYLDE chsmber bull barrel a few years ago and it shot great from the beginning.
BTW, if you are worried about a muzzle device causing issues, try shooting it without one installed. I did it during my debugging procedues and found that it made no difference in my case.
Good luck.
UPDATE
Got the WOA barrel in and went to the range. I typically shoot 6 shots, clean the barrel. Did this 3-4 times. Total wise I shot 118 rounds and the last few groups were under a 1moa at 100. I was tired and ready to go home so not my best shooting by any means.
Something I notice. The gas block on the Compass Lake was loose fit, however on the WOA I had to wiggle and push to harder to get it on and lined up.
Also saw the gas tube was touching the receiver with the Compass. I've never heard of gas tube causing such inaccuracy issues. When installing the WOA I made darn sure the gas block was line up and the tube was free of the receiver. It only touches on the top of the gas hole opening in the receiver.
i have 20 inch Krieger sourced from Brownells, chambered by Krieger i believe. it's a 1 in 7.7 twist. try 73 gr Bergers, (non VLD's) with Varget or Reloader 15. around 22.5 t0 23 grs works. from a rest off the bench it 's shooting in the .3's to .5's consistently, 5 shot groups. awesome bullet
elephantrider
01-28-16, 13:36
Shooting prone and using a rear bag at 100 yards I get groups of 1-1.5 moa. To be fair I have not shot semi in a while but when I did I got 1/2 - 3/4 moa. I was taught how to shoot a bolt gun, but not a semi. I often hear you have to "drive it" different. What that differences is? I do not know. So it could be me but I honestly doubt it as I record where the crosshairs were when the trigger broke.
Difference between a bolt rifle and semi-auto, is the recoil impulse. A bolt action has one recoil impulse, vs. the multiple things going on with an AR type semi auto during the firing cycle. "Driving," the semi-auto is controlling it through it's full recoil cycle and movement. Not uncommon for folks with lots of bolt gun experience to have this issue when moving over to a semi-auto, and it is even more pronounced w/ the larger .308/7.62mm sized cartridge platform as the recoil and reciprocating masses are even larger than .223/5.56. In other words, bolt guns are more forgiving of less than perfect shooter inputs than semi-autos are. If you head on over to the Snipershide.com forum, I believe there are some free videos on semi-auto vs. bolt gun lessons that may explain it a little better.
It sounds like you may have had a barrel issue that you sorted out, but I felt it was important to bring up the 'software' issue as well b/c it remains a factor even if all the gear related issues are sorted out.
elephantrider
01-28-16, 13:39
I generally square and true the crown on all my AR's this can make a big difference.
C4
Sent from my iPhone using Tapatalk
Grant, what crowning method are you using for this? Lathe? Hand tools? Are you doing a 90 degree muzzle face with a 45 at the rifling?
Grant, what crowning method are you using for this? Lathe? Hand tools? Are you doing a 90 degree muzzle face with a 45 at the rifling?
I would depends on the crown and if you deam the current crown's "shape" good.
Issue was a bur bur at the gas port. The bur was ripping the jacket.
KiloSierra
02-07-16, 21:51
Definitely try the muzzle device first. Last year I about drove myself batsh*t crazy about four weeks before a DMR championship match because my rifle suddenly went from a 3/4 MOA gun to something more akin to a shotgun. I tried everything, I even went so far as to buy a new barrel, which seemed to help and got me through the match finishing in the top ten. However the one thing that I didn't check was the muzzle device because had I done that I would have noticed that there was damage at the front aperture on the inside edge. After I slapped a different muzzle device on there accuracy went back to sub-MOA with ease.
I had the same thing happen to me with regular barrel once. Went from shooting 1-1.5" groups to shooting 3-4" groups all the sudden. Couldn't figure out what was going on till I was changing the flash suppressor out for a different type. Found out the when I had been cleaning it I hadn't been getting all the CLP and carbon out of the flash suppressor around the muzzle and it had built up till it was touching the bullet on one side.
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