M14 grouping all over the place - possibly busted scope

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Rosco7002

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So I took my M14 project gun to the range the other day, it was shooting all over the place! Groups at 100y were probably 8-9 inches, I would get a little cluster of shots on the bull but 2-3 shots just landed at random, causing an enormous “shotgun pattern”.

The rifle had been shooting very tight prior to this happening, my reloads were unchanged, my scope was on nice and secure. Gas parts had been cleaned just prior to but the rifle had not come out of the stock. Only reason I can think of is that the recoil may have been too much for the Bushnell 10x tactical scope?

Later this week I’m gonna shoot irons and run a box of FGMM to eliminate variables but anyone have any thoughts?
 
Did you shoot hand loads or factory? Iron sights is a good idea but you should use your most consistent ammo at the same time. What is the round count for the rifle?
 
What scope mount?
What stock?
Is the trigger group lockup tight?
How and why did you clean the gas parts? What parts specifically?

Theres a slew of possibilities, can you breakdown youre entire setup?
 
Check that your operating rod guide is tight and reasonably centered on the barrel. The bolt and operating rod assembled on the rifle without the recoil spring should be able to move freely without binding by tilting the receiver.
 
Thanks guys, here's some extra info:

AMMO - load is 41.4gr of H4985, BR2 primer, 168gr SMK and (fully prepped) Winchester brass. This has shot well for me but will be trying some factory ammo this week.

TEMPERATURE - No significant variance from when it was last shot.

TILT TEST - Was perfect 2 months ago, OP rod guide is epoxied in place, haven't checked recently bit will do so.

SET UP / RIFLE INFO - M305 w/TRW bolt, original but bedded plastic stock, tight trigger group lockup, CASM scope mount, vortex rings, Bushnell 10x elite tactical scope, shimmed gas system, trigger job, recrowned muzzle.

POSSIBLE SHOOTER ERROR - Cofident this is not a factor. Shot other platforms well on the same day + 2 different countries have spent mountains of cash training me to shoot in situations much more dynamic that a 100y static range.

RECENT CLEANING - Gas cylinder and plug were removed from the rifle w/barreled action left in the stock. Plug was put through a sonic cleaner, cylinder carbon was removed with brake cleaner and a brush. Parts were reassembled dry, no lube or oil.
 
re-crowned muzzle.......
how was this done? and have you inspected the chrome lining at the muzzle since firing it to see if it is peeling back or lifting?
that would be the first thing I would check based on your posts so far.

2nd would be the optic so I would remove it, bench the rifle well and shoot with iron sights , assuming they are of good quality..... a 5 or 10 round group at 75 to 100 meters and then again at 200 meters with something like Federal Power shok 150gr and check your groups. I suggest Power shok 150gr as whn i was building and tuning these guns, this ammo gave me the most reliability and accuracy of most off the shelf ammo for testing customer rifles (not smithing anymore btw).

if the rifle is still all over the place with quality irons , I would say the barrel is pooched.

I'd be curious to see what is happening at 200M
 
45ACPKING said:
......2nd would be the optic so I would remove it, bench the rifle well and shoot with iron sights..... if the rifle is still all over the place with quality irons, I would say the barrel is pooched
Click to expand...

Been thinking the same thing, if the scope is good the barrel has likely got a problem. Only about 500 rounds through this pipe but who knows, maybe a defect in there somewhere. Rifle is cycling well, no malfunctions or obvious issues with the action. If the scatter-shot replicates with the irons and factory ammo I’ll try some groups with the gas system turned off. Will also check the chrome link too.

I was planning to get a krieger or criterion soon so kinda hope that is it, buying new glass would suck.
 
Rosco7002 said:
Thanks guys, here's some extra info:

AMMO - load is 41.4gr of H4985, BR2 primer, 168gr SMK and (fully prepped) Winchester brass. This has shot well for me but will be trying some factory ammo this week.

TEMPERATURE - No significant variance from when it was last shot.

TILT TEST - Was perfect 2 months ago, OP rod guide is epoxied in place, haven't checked recently bit will do so.

SET UP / RIFLE INFO - M305 w/TRW bolt, original but bedded plastic stock, tight trigger group lockup, CASM scope mount, vortex rings, Bushnell 10x elite tactical scope, shimmed gas system, trigger job, recrowned muzzle.

POSSIBLE SHOOTER ERROR - Cofident this is not a factor. Shot other platforms well on the same day + 2 different countries have spent mountains of cash training me to shoot in situations much more dynamic that a 100y static range.

RECENT CLEANING - Gas cylinder and plug were removed from the rifle w/barreled action left in the stock. Plug was put through a sonic cleaner, cylinder carbon was removed with brake cleaner and a brush. Parts were reassembled dry, no lube or oil.
Click to expand...

Certainly narrows it down!

I agree irons are the way to go but with that CASM mount installed, I'm sure a healthy amount of loctite was used on the screws as per their instructions?
To save the aggravation of having to get that sucker off of there, clean the dried loctite from the screws AND the mounts threads (chase with a tap if you have them) install the irons and do it all over again, maybe confirm the mount is still solidly attached and try another scope first?

As 45acpking said, really check that muzzle and bore for flaking chrome lining. Clean it well, remove the flash hider and look the full length over with a bright light.

Also check to see if your flash hider is loose at all, if it is you may be getting bullet strikes. Look to see if u have any stripped copper jacket in there.
 
So I tested with irons yesterday. Groups were shot with the handloads described above + some 168gr FGMM (the latter has produced 1.25-2.0 MOA in the past).

Here's what happened:

- groups opened a little owing to the irons but,
(1) the FGMM stayed consistent in size.

(2) the handloads had flyers and, in one case, shot to 10.0 MOA. They also produced malfunctions which LOOKS like an extraction or short-stroke issue (1 case had to be pulled from the chamber with pliers, several stove pipes happened and the rifle failed to hold open on an empty mag several times). Also had a double feed which twisted one round all up to hell.

After the range I tore the gun down, cleaned it and inspected. Headspace is unchanged, tilt test is good. I DID note that there may be an alignment issue in the barrel to gas cylinder interface. An allen key which fits snuggly through the bottom of the cylinder won't go through into the barrel but a slightly smaller one will. 7.5 thou shims are being used here.

Here's what I think MIGHT be happening... the rifle is not cycling properly with the handloads and, as a result, it is damaging rounds when they get chambered. Which would cause the expanded groups.

Now, the load I'm using is pretty standard BUT maybe it is either; underpowered for this rifle? I'm also considering that the possible issue with gas system alignment is could also be the culprit.

Any other suggestions?
 
do you have a friend close by with an m305?
if so, borrow his piston and try it in your rifle
if your problems persist you can rule out the piston.

Sounds to me like maybe your rifle might be best served with a trip to the M14 Medic for a professional hands on inspection.
 
Rosco7002 said:
So I tested with irons yesterday. Groups were shot with the handloads described above + some 168gr FGMM (the latter has produced 1.25-2.0 MOA in the past).
Click to expand...

What were the group sizes with the FGMM in your latest attempt, and were they consistent in POI from group to group? Also, when you say the brass was fully prepped, does that mean full-length resized?
 
I would make sure of the brass , especially if they have been fired a few times through the m305 . I have a NM Springfield and found the bolt wasn't closing completely ( completely freaked me out ) and was causing bad groups . I bought a wilson case gauge which showed me I need a small base sizer and can only use the brass 3 times safely . This is probably more touchy with the tight chamber of the NM but you may have a tight chamber too

Good luck
 
Is it the black Norinco plastic stock? If so, is the front face of the stock tip pressing against the flat of the stock ferrule? The stock ferrule is the sheet metal part that slides over the barrel and gas cylinder with a lip on it to hold the front of your stock in place. the lip should touch the underside of your stock tip, but the front face of the tip should not be pressed against the ferrule. There should be around 1/16" of clearance there.

Those norinco stocks are VERY often made a little too long at the nose and if it presses there, it will open up your groups quite a bit.

Also, I would try an outing with some known quantity factory ammo. Maybe some hirtenberger or some FMJ stuff like Remington UMC. See if it shoots better with that. If it does, then I'd suspect your loads not being right.
 
No contact with the front of the stock ferrule, trimmed that back when I did my bedding. Problem was repeatable with handloads, FGGM, Hirtenberger and Win. 7.62x51.

Have not been able to bottom things out but in the end that may have been a blessing... got frustrated at the same time as I saw Wolverine put their IDF kits on sale for $650.00. Oh ordered one of those + a NOS pre-2007 receiver from John (M14 Medic). I’m now building on that and the quailty is just a pure pleasure - barrel, bolt, receiver and trigger group look nearly new and the receiver specs out beautifully. The “problem rifle” is one of the 2016 cast receiver versions so I got a good feeling it’s gonna donate itself to the spare parts bin.
 
Rosco7002 said:
No contact with the front of the stock ferrule, trimmed that back when I did my bedding. Problem was repeatable with handloads, FGGM, Hirtenberger and Win. 7.62x51.

Have not been able to bottom things out but in the end that may have been a blessing... got frustrated at the same time as I saw Wolverine put their IDF kits on sale for $650.00. Oh ordered one of those + a NOS pre-2007 receiver from John (M14 Medic). I’m now building on that and the quailty is just a pure pleasure - barrel, bolt, receiver and trigger group look nearly new and the receiver specs out beautifully. The “problem rifle” is one of the 2016 cast receiver versions so I got a good feeling it’s gonna donate itself to the spare parts bin.
Click to expand...

Cast chinese receivers are not worth building on. Period.

Sounds like you will be much better off now. If you use the IDF barrel, make sure you gauge for throat erosion and muzzle wear. Some of the IDF barrels I got from that batch were shot out, others were OK. If you don't have a gauge, look to see if the chrome is peeling in the barrel throat just ahead of the chamber. If it is, chances are, it would gauge poorly and might be a rejectable part.
 
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