Jump to content
308AR.com Community
  • Visit Aero Precision
  • Visit Brownells
  • Visit EuroOptic
  • Visit Site
  • Visit Beachin Tactical
  • Visit Rainier Arms
  • Visit Ballistic Advantage
  • Visit Palmetto State Armory
  • Visit Cabelas
  • Visit Sportsmans Guide
Cinders

Can a gunsmith diagnose accuracy issues?

Recommended Posts

Hi all!

I'm still at it with my .308, trying to figure out a weird split pattern I'm getting.  Had to take a break during the Great Ammo Shortage of 'ought 20.

Also just found out my Timney trigger is defective 😞  So working on replacing that.

I'm getting a little fed up trying to find the problem with my rifle, it's a slow process of trying to borrow parts or to get to the range (or get ammo).  Would a gunsmith be able to diagnose my rifle?  It could be the barrel, the gas block, the compensator (swapped scope/mount out, roughly the same split pattern as before).

Thanks!

Share this post


Link to post
Share on other sites

Which Gunsmith?

Gonna throw a link up here to your previous thread..... then I'll read it :thumbup:

 

Share this post


Link to post
Share on other sites

Thanks for linking that!

Yeah, I tried a better scope with a different mount and the grouping got a little worse but with the same pattern (2 tight groups left and right of the aim point).

I did read your gas block reference, Rex, and I'm wondering if I can just run it by a real expert who can give me a more definite answer.  It is a process to get to a range (and find ammo), so I'm not so keen on slowly trying out a scope swap, removing compensator, re-torque barrel, taking apart gas block to see if I can figure out if it was touching something.

 

Also, good question: which gunsmith?  I'm asking is if this is even a thing to approach a gunsmith about.  

Share this post


Link to post
Share on other sites

If something is off on your rifle a good gunsmith should be able to find it. You should be able to just look at your gas block inside the rail and see it it's touching.

Share this post


Link to post
Share on other sites

A gunsmith is going to have to do a lot of the same things you can do. Take the rail off. That will eliminate anything touching the gas block or barrel. Set the magazine on a sand bag and shoot it at 25 yds or so.

Just change 1 thing at a time.

A gunsmith is going to have to take it to the range and shoot it too.

Share this post


Link to post
Share on other sites
On 6/10/2021 at 4:28 PM, shooterrex said:

Did you ever try another scope and mount? I also had a build showing erratic groups. Gas block was touching the rail .

I also have been seeing bad groups... today they were split... I made some previous posts about my shooting and grouping... Asking everybody about rings, scopes, ammo and brass, as well as my gas block.  It is, as Shooter Rex’s once was, about a business card clearance from the inside of handgaurd.  I did notice slight markings inside the handgaurd before, but today after closer inspection, I’m sure it is rubbing when the barrel harmonically whips.  I am going to tear it off this weekend and look at the gas port, and either reinstall a non-adjustable one with more clearance or grind some material off.  I definetely also had at least one distinct split group today...

Share this post


Link to post
Share on other sites
23 hours ago, Cinders said:

Also, good question: which gunsmith?  I'm asking is if this is even a thing to approach a gunsmith about.  

The only gunsmith I'd trust to diagnose an AR would be ADCO Firearms.  You'll have to call on the phone, and explain the situation - but there is no better commercial AR Gunsmith than ADCO.

https://adcofirearms.com/

Share this post


Link to post
Share on other sites

1st question what ammo are you using that has to be the first look to then look for other issues but if it is garbage in it is garbage out...

Share this post


Link to post
Share on other sites

I have seen this discussed on other forums and it seemed to be narrowed down, in at least one case, to be dependent on which side of the magazine the round came from. If firing from a full mag, rounds 1,3,5 had about the same POI and rounds 2,4, had a different POI. This possibility could be eliminated by only loading one rd in the mag at a time so that every shot originated from the same side of the mag. If the split grouping went away then that would be the likely cause. I don't know if or how the problem ever got fixed however.

Share this post


Link to post
Share on other sites
10 hours ago, mtrmn said:

I have seen this discussed on other forums and it seemed to be narrowed down, in at least one case, to be dependent on which side of the magazine the round came from. If firing from a full mag, rounds 1,3,5 had about the same POI and rounds 2,4, had a different POI. This possibility could be eliminated by only loading one rd in the mag at a time so that every shot originated from the same side of the mag. If the split grouping went away then that would be the likely cause. I don't know if or how the problem ever got fixed however.

That would definitely be because of the ejector...   Rounds feeding from the right side of the mag have to make that jump when chambering, because the ejector is on the left side of the bolt face.  Square-faced ejectors are the worst offenders causing this, especially in the large-frame ARs.

Share this post


Link to post
Share on other sites
6 hours ago, 98Z5V said:

That would definitely be because of the ejector...   Rounds feeding from the right side of the mag have to make that jump when chambering, because the ejector is on the left side of the bolt face.  Square-faced ejectors are the worst offenders causing this, especially in the large-frame ARs.

Simple enough. Now I understand more about the reasons behind the round ejectors.

Share this post


Link to post
Share on other sites
15 hours ago, mtrmn said:

Simple enough. Now I understand more about the reasons behind the round ejectors.

Exactly so.  :thumbup:

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...