Is it me or the rifle? 6.5cm accuracy...

[kentuckyMarksman]

I recently built a 6.5CM large frame AR. I used a JP barrel with the +2" gas system, JP bolt, Light Weight Bolt Carrier, JP Silent Capture Spring recoil system, Superlative Arms gas block, and a ZEV receiver set. It had a Scalarworks mount with a Vortex Viper PST gen2 scope (5-25x FFP).

Barrel currently has 115 rounds through it.

The gas block is adjustable, it is set to where the recoil is very light, the rifle reliably ejects all the spent cases at the 3 o clock position, and locks back on an empty magazine.

I've tried the following ammo:
Federal 140gr NonTypical Whitetail
Hornady Gunner 140gr
S&B "Tactical" 140gr
Sig 140gr OTM
Sig 120gr Solid Copper hunting ammo
Winchester 120gr "Target" ammo

Best groups have been from the Winchester 120gr, those groups have been about 1.1" at 100yd. The different Sig ammo has been about 1.2". Everything else has been about 2".

I know I'm not using top shelf ammo, but I would expect at least 1 group under an inch at 100 yards. I'm just shooting what I can get my hands on locally. Anyone else have my same barrel and might have a suggestion on factory ammo to try?

Been saving my brass, and I do intend on reloading for this rifle.


Update - borrowed the scope and mount from a relative's rifle and put on my rifle. My groups shrunk dramatically, down to .6" with factory Hornady. Much better than 2.5-3" I was getting before. I had checked torque on my scope mount numerous times. I think I may have an optic issue. Will try putting that scope on a bolt gun to confirm the issue.

 

[JasonB]

How are you at shooting other AR Rifles? If you can shoot tight with another AR10 style then it probably isnt you and it is your ammo/rifle combo ... have some that shoots AR10s well try it

 

[deersniper]

Have you shot semi autos accurately before? Particularly large frames?

If not have someone else shoot it. And check out the online training here. It goes over shooting semi autos accurately and al that goes into.

A big thing is follow through. Plus all the other fundamentals. A semi auto will punish fundamentals that aren’t rock solid. While bolt actions and smaller calibers will let you get away with more

I get 5 shot groups way way under 1” with a cf proof barreled sp10 with Hornady American gunner and match 140 eld.

 

[kentuckyMarksman]

How are you at shooting other AR Rifles? If you can shoot tight with another AR10 style then it probably isnt you and it is your ammo/rifle combo ... have some that shoots AR10s well try it

There are several SPR small frame builds that I can shoot 1 MOA with Hornady Black. Could probably go smaller with some load development.

Have you shot semi autos accurately before? Particularly large frames?

If not have someone else shoot it. And check out the online training here. It goes over shooting semi autos accurately and al that goes into.

A big thing is follow through. Plus all the other fundamentals. A semi auto will punish fundamentals that aren’t rock solid. While bolt actions and smaller calibers will let you get away with more

I get 5 shot groups way way under 1” with a cf proof barreled sp10 with Hornady American gunner and match 140 eld.

I'm about a 2 MOA shooter with a stock M1 Garand, a little better with a M14. This is my first large frame AR, but I do have experience shooting matches with the above semi auto rifles.

I've been shooting this 6.5CM with an Atlas bipod in the front and a sandbag in the rear. I'm amazed at how little recoil this rifle has, it's softer than a 223. I'm just surprised the groups aren't better.

 

[kentuckyMarksman]

Does gas adjustment affect group size? I'm pretty happy with the current gas setting, but can adjust it if needed.

 

[NH4X]

If you're not cleaning the barrel between different boxes and different brands of ammo.........you're chasing your tail .There are people that know way more than i do that have spoke about and/or put it in print . They've tested and proved ( to themselves) that it can take a few , to quite a few rounds of diff.ammo for a barrel to settle back in. Ymmv

 

[deersniper]

I’m saying shooter error. Hornady American gunner shoots very well at 100 in every match barrel I have tried it in

 

[redneckbmxer24]

If you're not cleaning the barrel between different boxes and different brands of ammo.........you're chasing your tail .There are people that know way more than i do that have spoke about and/or put it in print . They've tested and proved ( to themselves) that it can take a few , to quite a few rounds of diff.ammo for a barrel to settle back in. Ymmv

This is certainly something to consider, combined with less than stellar ammo choices, and it being a large frame.

 

[RobbinsHGray]

Seems like a simple answer to me. Find a good shooter, you shoot it they shoot it, you shoot it. If their groups are good it’s you. If no groups are good it’s in the setup somewhere. Is the scope tight in the rings?

 

[Halfnutz]

Have you shot semi autos accurately before? Particularly large frames?

If not have someone else shoot it. And check out the online training here. It goes over shooting semi autos accurately and al that goes into.

A big thing is follow through. Plus all the other fundamentals. A semi auto will punish fundamentals that aren’t rock solid. While bolt actions and smaller calibers will let you get away with more

@kentuckyMarksman, you are not the first or the last person to ask this, including myself. Deersniper is spot on IMO.
I struggle with my own large frame AR, It is a different animal. You (I) really have to work your (my) fundamentals to get it to perform.

DO the online training, LL will point out things about the gassers, and a bunch of other topics, not to mention you support the site and there is a plethora of information there for less than $20.

 

[Bullspotter]

When I started shooting large fram ARs, i had a lot of variation in my groups from day to day. Had to sit and think about things. It was all in handling the recoil, (moving parts in a gun) Shooting off a bipod and a rear bag, i pull gun into shoulder with plenty of firmness, not to much to make me shaky or fatigued, but enough to know im pulling the gun into my shoulder. then push my body and rifle forward loading some pressure on bipod legs. This seems to make the aiming part more steady as well as control the beginning of recoil and the start of wight moving in the rifle. Lastly i pull though the shot, trigger is pinned back, and i do not move my cheek weld or head, and try to keep everything firm.

 

[kentuckyMarksman]

@kentuckyMarksman, you are not the first or the last person to ask this, including myself. Deersniper is spot on IMO.
I struggle with my own large frame AR, It is a different animal. You (I) really have to work your (my) fundamentals to get it to perform.

DO the online training, LL will point out things about the gassers, and a bunch of other topics, not to mention you support the site and there is a plethora of information there for less than $20.

Yeah, I think you are probably right. Not really pulling the rifle into my shoulder. I shoot a lot of bolt gun for accuracy, just now getting into gassers. I've got bolt guns I can shoot .5" groups at 100. I think you are right, large frame ARs are a different animal.

I'll look into the online training. Is it $20 per month?

I'm going to do some load development as well. I know I may be wasting my time, but it may tell me something.

 

[deersniper]

A small sample :

 

[Halfnutz]

Yeah, I think you are probably right. Not really pulling the rifle into my shoulder. I shoot a lot of bolt gun for accuracy, just now getting into gassers. I've got bolt guns I can shoot .5" groups at 100. I think you are right, large frame ARs are a different animal.

I'll look into the online training. Is it $20 per month?

I'm going to do some load development as well. I know I may be wasting my time, but it may tell me something.

I think its $18 per month iirc. Less than a box of 9mm and worth it. I think you can cancel anytime. I sound like an infomercial.

Lock time and cycling is way longer on a gasser. Follow through, follow through, follow through.
I say that on here alot, I shoot air pistol occasionally and the break and the follow through will make or break you.

 

[Roslyn]

For what it is worth, you might try the Eagle Eye or Hornady ammunition. I shoot the standard JP LRP-07 with a 22" barrel, and it will print .5 MOA groups using the Eagle Eye 130 gr and 140 gr Berger hybrid rounds. it shoots the Hornady 140 gr ELD-M not quite as well, maybe .75 MOA. That said, it won't shoot Prime 130 gr or the Hornady 129 gr worth a damn, easily 2 inch groups at 100 yards.

All the other comments about your fundamentals obviously the starting point.

 

[mhines]

My ar10 is based on almost the upper setup, same barrel, bolt, capture spring just different gas block, that you have.
Shoots hornady american gunner 140gr at .75 moa all day and handloads at .5 moa

As people have said shooting a large frame ar is not the same as a bolt action so i would start with validating form or having someone else give it a go.

 

[FALex]

I’m saying shooter error. Hornady American gunner shoots very well at 100 in every match barrel I have tried it in

OP what trigger are you running?

I would second this from @deersniper too. I have been surprised, time and again, on how well that American Gunner shoots.

 

[deersniper]

Trigger is important too. A heavy trigger just makes accuracy more difficult.

I run Larue 2 stages and Geisselle NM triggers. The Larues are the best bang for the buck

 

[FALex]

Trigger is important too. A heavy trigger just makes accuracy more difficult.

I run Larue 2 stages and Geisselle NM triggers. The Larues are the best bang for the buck

We must be long, lost twins, friend. I literally just got done saying that about 4 hours ago to my brother. I have a Geissele SD3G in an SR-15, and it is an outstanding trigger. When my bro learned how much it cost, he about shit himself. He then looked at the still-uninstalled MBT on the shelf and pointed to it. I said, "that there is likely the best AR trigger for the money." Although I prefer single stage triggers, I roll with the two stage MBT's only because the single stage don't break until 6-6.5lbs. The two stage goes at 4.5.

 

[nikonNUT]

I may just be lucky but my 6.5CM gasser will happily print sub-.5 MOA group all day long and it's a Savage MSR-10 I added a Trigger Tech Diamond AR and that seemed to help a LOT (and I have it running very light)! I would also try the Honday 140gr match stuff. That round really rocks in my rifle and I am a piss poor shooter. American Gunner ain't bad either but groups do suffer just a tad...

P.S. My rifle didn't really get "right" until I was about 300 rounds in. Don't know if that matters.

 

[D1gger]

If you're not cleaning the barrel between different boxes and different brands of ammo.........you're chasing your tail .There are people that know way more than i do that have spoke about and/or put it in print . They've tested and proved ( to themselves) that it can take a few , to quite a few rounds of diff.ammo for a barrel to settle back in. Ymmv

That's a new one to me, but to be fair, once I find a load, I stick to it and don't change it up.
I got freaking railed by a few members recently when I was questioning weird velocities out of a new AR15 build that only had about 50 rounds on it, as the barrel was still settling in. IMHO, at 115 rounds, the barrel is ready for a good post break-in cleaning. After that, I let mine go until I see the accuracy starting to fall off, which tends to be around 500 or so.
And what everyone said about triggers too. You should also hear your trigger reset well after the shot. I've had guys ask why my rifle is clicking after the shot-it was just resetting

 

[Len5E1]

Hard to say if it's you or the rifle. I was always a pistol shooter until I got interested in long range and decided to build a very similar setup as yours with JP everything but a aero m5e1 receiver set. I also went 308 instead of 6.5 at the time - I had very little experience shooting rifles at all, much less for precision but I did watch a lot of videos and get a good understanding on the fundamentals of precision shooting and tried them out after completing the rifle build. I even have the same scope as you. After doing what I thought was a good middle grounds for the barrel break in it was very easy to get sub MOA 5 shot groups at 100 yards. I took the rifle out to 300 yards outdoors and got a .33 moa group with it. I've only used factory hornady black and federal GMM so far. Knowing my experience level and limited practice before this rifle I have full confidence in JP's barrels.

I didn't see a trigger mentioned - what trigger are you using? Are you using bags or bipod? I have a geiselle high speed national match setup pretty light and I use a harris bipod typically but I get the same groups laying the handguard on a bag. Either there is something clearly wrong with your rifle somewhere (because it should be .5-.75 moa capable) or you are doing something wrong.

 

[kentuckyMarksman]

Several users here are asking about my trigger, it's a Geissele SSA-E.

I'm also using an Atlas bipod in the front, and a sandbag in the rear.

 

[deersniper]

.

I'm also using an Atlas bipod in the front, .

What atlas?

Not a fan of the psr

 

[nikonNUT]

What atlas?

Not a fan of the psr

Ditto... When I went to try my hand at 1k I left the PSR at home and instead swapped the ARCA clamp for a QD mount on my 5-H and took it. Night and day difference in performance!

 

[kentuckyMarksman]

What atlas?

Not a fan of the psr

Atlas CAL BT65. Not a PSR fan either.

 

[kentuckyMarksman]

Had another shooter, a former AR10 owner in 6.5cm shoot it the other day. His groups were slightly larger than mine with the gun. He sold his rifle about a year ago, so maybe we both are sucky shooters.

Don't know anyone else in my area with a large frame AR. I have an inlaw that shoots small frame AR all the time, might have him try.

Scope and mount seem like they are installed securely. Screws holding the scope on were torqued properly.

Might try a different scope, just to rule an optic problem out.

 

[striped1]

Have you checked your barrel torque? My experience is that you should be at the top of torque spec range. Clearance between gasblock and handguard correct? Not enough clearance there can also cause issues.

 

[Len5E1]

This might sound dumb but did you triple check your scopes mounting system isn't loose?

This has to be a rifle issue not a skill issue. Finding someone used to ar platform isn't the answer, I really don't think this is a skill issue. There's some pretty novice and newer shooters that can easily do 1 MOA at 100 with a capable AR without any special precision training. I really think something is up with your rifle because there's TONS of sub MOA ar10's and a good amount of quality half MOA ar10's as well. You just gotta track down the issue. I was getting some bad groups one time and didn't notice half of my ADM QD Mount was loose and causing just enough movement under fire to ruin my groups entirely, dumb mistake but I was happy when I realized what was going on!

 

[bfoosh006]

I suggest you work on your bench shooting form when firing a Large Frame AR... I sure learned a lot.

Be sure to hold the stock snug against the shoulder ( and for me ) with little to any downward pressure ) , I don't release the trigger until everything has quit moving.

I also shoot far better off a bag and squeeze bag on the back , over a bipod... so maybe try a bag setup.... and make sure your recoil impulse is straight back.... no off to the side deflection at all.

Large Frame AR's ( regardless of the well tuned and light recoil , which is awesome , mine are the same , but with a heavy buffer and recoil setup ) sure seem to like me to keep my position rock steady until well after the recoil impulse.

And be sure to not adjust ANYTHING while shooting for precision... as in nothing !! ... No fidgeting, no... my cheek wield isn't quite right, no... "I'll just reposition the stock a little ... hold you position rock steady until you are done with your amount of rounds.

If the group is off to the side of your POA... that allows you to keep aiming at a precise, same point on the target... make sure that POA is small... I put a black dot on the center of a 1" red paster. Or in a pinch aim at the top 1" red dot. ( aim small , group small... is what it used to be called ? )

I would also suggest you clean the barrel.... I know your round count is low, and the JP is a hand lapped barrel... but you might get some outstanding group improvements..... I suggest some Kroil, JB Bore Polish, and the VFG felt Pellets ... all at Brownells and be sure to get the adaptor for your cleaning rod. ( no bronze brushes for me ever again. )

After cleaning with the above products I have had 10rd sub MOA groups that surprised the poop out of me. With Hornady AG 140gr 65CM and Hornady AG 155gr 308. Be sure to watch some of Brownells videos about the above cleaning products )

I am also a FIRM believer in not firing one ammo brand for precision and then firing another brand for precision. I always let the barrel "season" into the next factory load. I fire 5 throw away rds ... then fire for precision.
( Or try an experiment... fire one load after another different factory load... but watch for the first 5 rounds slowly group tighter from the following ammos... )

I have no scientific proof.... but I have fired hundreds and hundreds of 10rd groups from a variety of factory loads.

I have witnessed a "trend" of 10rd groups that would slowly tighten up as I fired ( blatantly noticeable ) when firing one factory load, then another...

Does it happen everytime... nope... but it certainly happened enough for my feeble, dimwitted mind to notice.... ( Lol )

After I noticed I could watch it happen over and over.

So I always season the barrel to the next ammo to try .

 

[Len5E1]

And be sure to not adjust ANYTHING while shooting for precision... as in nothing !! ... No fidgeting, no... my cheek wield isn't quite right, no... "I'll

So what bfoosh said is very accurate and you probably already know is great precision practice advice. Obviously the key to precision is repetitive consistency and if you can't do that then you are sacrificing accuracy. That said, as I mentioned, I have quite little experience with rifles and precision and even to this day probably only have 200-300 rounds through my JP AR10 and that's the extent of my experience with a non 223 semi-auto. With that in mind, I was getting sub MOA groups the very first time I took out my AR10 at 100 yards. I watched lot's of videos and learned a lot ahead of time and put it into practice right away but one thing I remember is not to adjust your positioning and such like bfoosh mentioned while shooting groups. Since I've owned this ar10 I constantly switch up my aim, cheek weld, seating position etc while trying to find and learn the best way. At 100 yards it makes a very small difference and getting .75 MOA groups is stupid easy. I'm only saying this because although my experience will show at 600 yards it's truly not hard to group a 100 yard sub moa group even in an AR10 with NO experience. I still think this is a rifle problem and not a YOU problem. I could be wrong of course.

( no bronze brushes for me ever again. )

What's the deal with bronze? I haven't been keeping up with much lately but I'm curious because I don't want to cause additional wear to my JP barrel if there's better options to keep it clean. What issues have brass caused you?

 

[loveha]

I don't think bronze hurts anything, I mean, steel is much much harder than bronze. Never used the pellets, but all my brushes are nylon. Mostly because I don't want false positives when cleaning with Boretech. And nylon gets the job done just as good, maybe if not better. I almost feel as if nylon brushes are stiffer.

 

[russkim04]

Have a friend fire it, see if it's you

 

[kentuckyMarksman]

Have you checked your barrel torque? My experience is that you should be at the top of torque spec range. Clearance between gasblock and handguard correct? Not enough clearance there can also cause issues.

I haven't checked my barrel torque yet. Pretty sure I torqued it to 65ft pounds. Will double check though.

I do believe I have plenty of clearance between the gas block and the handguard. I have .1" of clearance above the gasbock, .08" of clearance on both sides, and .0625" on the bottom. It takes a good bit of force to squeeze hard enough for it to make contact.

This might sound dumb but did you triple check your scopes mounting system isn't loose?

This has to be a rifle issue not a skill issue. Finding someone used to ar platform isn't the answer, I really don't think this is a skill issue. There's some pretty novice and newer shooters that can easily do 1 MOA at 100 with a capable AR without any special precision training. I really think something is up with your rifle because there's TONS of sub MOA ar10's and a good amount of quality half MOA ar10's as well. You just gotta track down the issue. I was getting some bad groups one time and didn't notice half of my ADM QD Mount was loose and causing just enough movement under fire to ruin my groups entirely, dumb mistake but I was happy when I realized what was going on!

I checked, the mount was good and tight, but the screws holding the scope in the mount were inconsistent. Some were only torqued to 12 inch pound, and some at 16. I snugged all the screws up to 20 inch pounds. Hopefully that makes a difference.

 

[kentuckyMarksman]

I suggest you work on your bench shooting form when firing a Large Frame AR... I sure learned a lot.

Be sure to hold the stock snug against the shoulder ( and for me ) with little to any downward pressure ) , I don't release the trigger until everything has quit moving.

I also shoot far better off a bag and squeeze bag on the back , over a bipod... so maybe try a bag setup.... and make sure your recoil impulse is straight back.... no off to the side deflection at all.

Large Frame AR's ( regardless of the well tuned and light recoil , which is awesome , mine are the same , but with a heavy buffer and recoil setup ) sure seem to like me to keep my position rock steady until well after the recoil impulse.

And be sure to not adjust ANYTHING while shooting for precision... as in nothing !! ... No fidgeting, no... my cheek wield isn't quite right, no... "I'll just reposition the stock a little ... hold you position rock steady until you are done with your amount of rounds.

If the group is off to the side of your POA... that allows you to keep aiming at a precise, same point on the target... make sure that POA is small... I put a black dot on the center of a 1" red paster. Or in a pinch aim at the top 1" red dot. ( aim small , group small... is what it used to be called ? )

I would also suggest you clean the barrel.... I know your round count is low, and the JP is a hand lapped barrel... but you might get some outstanding group improvements..... I suggest some Kroil, JB Bore Polish, and the VFG felt Pellets ... all at Brownells and be sure to get the adaptor for your cleaning rod. ( no bronze brushes for me ever again. )

After cleaning with the above products I have had 10rd sub MOA groups that surprised the poop out of me. With Hornady AG 140gr 65CM and Hornady AG 155gr 308. Be sure to watch some of Brownells videos about the above cleaning products )

I am also a FIRM believer in not firing one ammo brand for precision and then firing another brand for precision. I always let the barrel "season" into the next factory load. I fire 5 throw away rds ... then fire for precision.
( Or try an experiment... fire one load after another different factory load... but watch for the first 5 rounds slowly group tighter from the following ammos... )

I have no scientific proof.... but I have fired hundreds and hundreds of 10rd groups from a variety of factory loads.

I have witnessed a "trend" of 10rd groups that would slowly tighten up as I fired ( blatantly noticeable ) when firing one factory load, then another...

Does it happen everytime... nope... but it certainly happened enough for my feeble, dimwitted mind to notice.... ( Lol )

After I noticed I could watch it happen over and over.

So I always season the barrel to the next ammo to try .

Thanks, I've been putting my shoulder into the rifle, and not releasing the trigger until everything has stopped moving. For the last few range trips, I've been cleaning my barrel each time before I go, and only firing 1 type of ammo per trip. Groups may have tightened up a little, but they still suck.

I've been shooting at 1" stickers with a tiny dot right in the center. I think that target is sufficient.

I've since tightened up my scope in the mount, and I'll try shooting off a front bag and see if that makes a difference.

So what bfoosh said is very accurate and you probably already know is great precision practice advice. Obviously the key to precision is repetitive consistency and if you can't do that then you are sacrificing accuracy. That said, as I mentioned, I have quite little experience with rifles and precision and even to this day probably only have 200-300 rounds through my JP AR10 and that's the extent of my experience with a non 223 semi-auto. With that in mind, I was getting sub MOA groups the very first time I took out my AR10 at 100 yards. I watched lot's of videos and learned a lot ahead of time and put it into practice right away but one thing I remember is not to adjust your positioning and such like bfoosh mentioned while shooting groups. Since I've owned this ar10 I constantly switch up my aim, cheek weld, seating position etc while trying to find and learn the best way. At 100 yards it makes a very small difference and getting .75 MOA groups is stupid easy. I'm only saying this because although my experience will show at 600 yards it's truly not hard to group a 100 yard sub moa group even in an AR10 with NO experience. I still think this is a rifle problem and not a YOU problem. I could be wrong of course.


What's the deal with bronze? I haven't been keeping up with much lately but I'm curious because I don't want to cause additional wear to my JP barrel if there's better options to keep it clean. What issues have brass caused you?

I'm used to shooting a match grade M14 in CMP and High Power matches. Consistency is very important.

 

[oneshot onekill]

Have you shot semi autos accurately before? Particularly large frames?

If not have someone else shoot it. And check out the online training here. It goes over shooting semi autos accurately and al that goes into.

A big thing is follow through. Plus all the other fundamentals. A semi auto will punish fundamentals that aren’t rock solid. While bolt actions and smaller calibers will let you get away with more

I get 5 shot groups way way under 1” with a cf proof barreled sp10 with Hornady American gunner and match 140 eld.

+1 to this...
I've always shot bug-holes with good Bolt rifles but until recently couldn't seem to do the same with a Gas gun when the gun was proven accurate by better shooters. I'm better now but you do really have to pay attention to your fundamentals.

 

[bfoosh006]

What's the deal with bronze? I haven't been keeping up with much lately but I'm curious because I don't want to cause additional wear to my JP barrel if there's better options to keep it clean. What issues have brass caused you?

Ever since I started using the VFG felt Pellets , Kroil, and JB Bore Polish... the bore comes much cleaner, and also faster.

I have a bunch of bore scope pics at home from "before and after" VFG, Kroil and JB Bore polish. , virgin barrels as well as higher round count barrels.

So I just ditch bronze brushes... because of the faster and easier cleaning. You can readily "adjust" how much "tension" the felt pellets have through the bore... simply by screwing them tighter ( or unscrewing for a looser fit ) onto the adaptor.
You can easily make the "fit" so snug they won't slide into the bore

My bore scope has shown me how much more effective cleaning the Felt pellets are.

And no more wondering about the chosen cleaner destroying the bronze brush.

Ditching the bronze brushes has noting to do with additional wear in my case.

 

[kentuckyMarksman]

Have you checked your barrel torque? My experience is that you should be at the top of torque spec range.

Checked the torque on my barrel nut today. 65 foot pounds, which is right where ZEV recommended (I have their rail).

 

[kentuckyMarksman]

Update in OP. I think I have an optic issue.

 

[BikePilot]

Glad you found the issue. You have great parts in that gun and it should be around half moa with good factory match grade ammo. Assuming the scope isn't moving in the mounts and you've got the diopter and parallax adjusted correctly, I'd send it back to Vortex.