Stag 10 Left Handed Model Marking Up Brass

ljones

ljones

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I got my Left Handed Stag 10 GI set up and to the range. Works fine except for marking up the shoulder and neck of the fired brass. 2 parallel scratches. Even raising burs in the brass on the case neck. Rifle feeds, fires and ejects fine. But want to reload the brass but this is marking them pretty bad and not sure if it will compromise the case neck if reloaded. Not sure if this is due to the fact it is ejecting to the left as opposed to ejecting to the right like most AR's. Would it be burrs in the chamber or would it be marking up the brass on the locking lugs on ejection? I chambered and ejected a few rounds without firing to see if I could see anything on the brass but not able to see these marks. But don't know if it has to be fired and the brass expand in the chamber for it to show from burs in the chamber or if it is in fact being marked by ejection. Am I worrying needlessly or is this normal for brass out of an AR 10. This is the first AR10 I have fired. Had a BCL 102 but sold it before using it when I saw the Stag 10 lefty version was available. Any insight would be appreciated. Here are some pics of the fired brass.

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I imagine that it is unlikely to be from the chamber, it appears that the gouges are going in the reverse direction, i.e. starting at the shoulder and ending at the case neck - which might indicate that the case necks/shoulders are contacting on the locking lugs of the barrel extension. Perhaps you could try putting sharpy/marker on the cases, and attempt to recreate it - that may show where the contact is happening.
 
I had similar marks on my brass when I assembled my SLR and JP tech support told me that once the barrel extension wears in with the bolt after a few hundred rounds the gun should be easier on brass. Mine no longer leaves marks on the brass.
 
BooSSted said:
Is it just on the one side? Is it a Stag barrel? Check the feed ramp for sharp edges.
Click to expand...

It is the Stag barrel. I don.t think it is the feed ramp as I cycled a few mags of unfired through the action without firing and there were no marks. Only on fired ejected brass. Hopefully it is just a break in issue that will resolve with use.
 
ljones said:
I got my Left Handed Stag 10 GI set up and to the range. Works fine except for marking up the shoulder and neck of the fired brass. 2 parallel scratches. Even raising burs in the brass on the case neck. Rifle feeds, fires and ejects fine. But want to reload the brass but this is marking them pretty bad and not sure if it will compromise the case neck if reloaded. Not sure if this is due to the fact it is ejecting to the left as opposed to ejecting to the right like most AR's. Would it be burrs in the chamber or would it be marking up the brass on the locking lugs on ejection? I chambered and ejected a few rounds without firing to see if I could see anything on the brass but not able to see these marks. But don't know if it has to be fired and the brass expand in the chamber for it to show from burs in the chamber or if it is in fact being marked by ejection. Am I worrying needlessly or is this normal for brass out of an AR 10. This is the first AR10 I have fired. Had a BCL 102 but sold it before using it when I saw the Stag 10 lefty version was available. Any insight would be appreciated. Here are some pics of the fired brass.
Click to expand...

Mine was leaving brass curls and cutting into the bullet as well as the case. After the first 100+ trip it was better. After today's 135 round trip it's now leaving marks like you have. (Great improvement as the brass curls would sometimes get into the chamber and jam it up.) I believe it's the feed ramp as the chamber looks fine under bright light and 3x glasses.

I keep running 50% brass cases and 50% steel from different sources, Norinco, TulAmmo, Barnaul, and MFS. I'm hoping the steel cases smooth things down faster. I didn't see andy shavings in the chamber or area this time but did see a fleck of brass on the bolt face once.

Not thrilled about it, would expect it from an M305 before the Stag-10, but it's not a show stopper.

Does your forward assist work properly? Mine doesn't contact the BCG. When I first took the rifle out I had to use my finger when I could or rerack the rifle as the chamber wasn't all the way closed, but it would still fire, just no bang. Now the forward assist still doesn't work but I didn't need it this trip, I watched for any gap each time. (I did have one light strike today that may be related but the cap looked like it was hit well. Second try it fired the round.)
 
^Doesn’t sound normal. Feel free to see if it stops with further use, and do tell if it does, but also feel free to contact us.
 
ARMS EAST said:
^Doesn’t sound normal. Feel free to see if it stops with further use, and do tell if it does, but also feel free to contact us.
Click to expand...

I did. :)

Sent two emails to AE, once last Friday after first outing and another either late Tuesday night or Wednesday, in case you needed time to check before replying. Stag Arms was CC'ed on the second email and I got read receipts but no reply as of early this morning.

I sent you a PM at, 10-24-2018, 11:23 AM, titled "Stag-10 small issues" pretty much saying the same thing as above in case that was seen before my emails. Guess I'll have to make some time to call you tomorrow.

Have a good night.

Zen
 
This is pretty normal for the 308 AR's. It's the lugs in the barrel receiver catching the brass upon ejection. If you load a piece of brass and slowly pull the BCG rearward you will see the contact points

My first build was bad for this so I lightly sanded the edges of the two lugs at 1-2 O'clock and installed the JP captured spring buffer setup. The lighter spring seemed to let the bolt open slightly faster and the brass began clearing the lugs. If this didn't cure it, I was going to go with a lighter extractor spring..

Edit: Just thinking that the new titanium BCG's might be light enough to cure this also..
 
dusticles said:
This is pretty normal for the 308 AR's. It's the lugs in the barrel receiver catching the brass upon ejection. If you load a piece of brass and slowly pull the BCG rearward you will see the contact points

My first build was bad for this so I lightly sanded the edges of the two lugs at 1-2 O'clock and installed the JP captured spring buffer setup. The lighter spring seemed to let the bolt open slightly faster and the brass began clearing the lugs. If this didn't cure it, I was going to go with a lighter extractor spring..

Edit: Just thinking that the new titanium BCG's might be light enough to cure this also..
Click to expand...

Do they make left handed titanium bolt carrier groups? Where else would you even find any? Most would be right handed wouldn't they?
 
dusticles said:
This is pretty normal for the 308 AR's. It's the lugs in the barrel receiver catching the brass upon ejection. If you load a piece of brass and slowly pull the BCG rearward you will see the contact points

My first build was bad for this so I lightly sanded the edges of the two lugs at 1-2 O'clock
Click to expand...
I’m with you to there, but prob 9-10 O’clock on the LH ;)

The barrel extension lugs in question here seem to have a sharp lip which is scratching the brass on ejection. It should wear in and stop on its own, but the process of dulling that edge can be accelerated.

There is no need to swap components to correct.
 
dangertree said:
I’m with you to there, but prob 9-10 O’clock on the LH ;)

The barrel extension lugs in question here seem to have a sharp lip which is scratching the brass on ejection. It should wear in and stop on its own, but the process of dulling that edge can be accelerated.

There is no need to swap components to correct.
Click to expand...

And how would you accelerate the wear in process?
 
After looking into the cause a little further this weekend, at least on my rifle, it looks like the feed ramps still scrape the bullet and case when stripped from a magazine, just not to the extent they did 250 rounds ago. The barrel extension lugs at the 2 o'clock position seem to scrape the case further when ejecting the case.

If a cartridge is dropped into the chamber manually, without the help of the action, no marks are found on the cartridge even after the bolt is closed. If the cartridge is then extracted by pulling back on the charging handle while using a finger to keep the cartridge off of the lugs no marks are left on the cartridge.

As noted earlier mine have gone from heavy scrapes prior to first fire to looking about the same as the ones in the first post. The scratches on the bullets and neck are thinner and much less pronounced now but still have a slight twist when fed by the magazine.

No email reply from AE yet so I'll have to call them next week as they aren't open on the weekend about my forward assist and missing straps for my case.
 
Just a quick update; AE and SA have both gotten back to me and the missing straps and failed parts are being sent by Monday. The RMA process is two stage right now but still being streamlined. No BS, excuses, or mucking around. Arms East listened, asked a few questions, and already had things in motion before I was able to hang up and call Stag.Stag confirmed that they had just been contacted and hoped to have things out to AE by end of day. They even had a few suggestions to speed up the wear of the barrel extension lugs since mine are so sharp.

Once the new parts arrive I'll get out for a third test day and post all the results together.


Best 5 shot groups at 80m, rounds ranging from 140gr to 150gr; (Shot while sighting in a 1-4x24 Millett off a folding table and bipod.)

140gr MFS SP bought two years ago - .75" (The new Barnaul aren't even close to this.)

147gr China Surplus FMJ two years ago - 1" (Other two groups were 2" so surprise.)

146gr Hirtenberger 146gr FMJ new - 1.25" (Would have been .75" but for a flyer.)


Need to get some heavy rounds, seems testing at the start of hunting season wasn't the best time to buy ammo. ;)
 
Zen_Seeker said:
Just a quick update; AE and SA have both gotten back to me and the missing straps and failed parts are being sent by Monday. The RMA process is two stage right now but still being streamlined. No BS, excuses, or mucking around. Arms East listened, asked a few questions, and already had things in motion before I was able to hang up and call Stag.Stag confirmed that they had just been contacted and hoped to have things out to AE by end of day. They even had a few suggestions to speed up the wear of the barrel extension lugs since mine are so sharp.

Once the new parts arrive I'll get out for a third test day and post all the results together.


Best 5 shot groups at 80m, rounds ranging from 140gr to 150gr; (Shot while sighting in a 1-4x24 Millett off a folding table and bipod.)

140gr MFS SP bought two years ago - .75" (The new Barnaul aren't even close to this.)

147gr China Surplus FMJ two years ago - 1" (Other two groups were 2" so surprise.)

146gr Hirtenberger 146gr FMJ new - 1.25" (Would have been .75" but for a flyer.)


Need to get some heavy rounds, seems testing at the start of hunting season wasn't the best time to buy ammo. ;)
Click to expand...

What are these missing straps that you're referring to, please?

Thanks,

Tom
 
I'm having the same issue with my Stag. I'm not stressed about it really. I only have 35 rounds down the 6.5 Creedmoor barrel. Perhaps the locking lugs will wear in and reduce or eliminate the gouges on the case necks but I am going to use a some cratex and a little elbow grease to lightly smooth/polish the sharp edges of the lugs where necessary. Just need to get around to it. Love my Stag 10!
 
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