Kit build adjustment help, (headspace, Bolt catch)

[tapcaf]

First post here, I've been looking at a lot of the threads fixing issues with my build, I didn't realize how much of an issue  sourcing parts was going to be due to not having a mil-spec variation or people trying to sell you parts for a 15 that doesn't fit a 308, (30% of my buddies pistol build was my gimmes) So far  I'm down to two major issues one minor.

1. Headspace is at minimum possibly below what should a fully engaged lug look like. I can still a sliver of bolt lugs peeking out around the chamber lugs, I was able to get a 1/1000 feeler gauge nest to it about the same I was thinking about removing the coating off the bolt face to see if it will flush up.

2.The other issue is where the upper meets with the lower it is stopping my mag from entering the 10% of the way, if I pull the pin hinge the upper mag locks in then close pin back in works fine cycled manually it with five snap caps. AS soon as I drop the mag no binding gravity pulls it out, can't put in another tried different mags same thing. it's hitting the upper been thinking just sand off a few layers with my dremel (upper is a P.S.A mk1 lower is a Tennnessee arms hybrid lower)

3.Minor issue: bolt catch not locking this might be switched springs (I've taken the detent out once already that was stuck in the spring) saw it on another post on here, the bolt catch should be for a 10 I got it in a lower kit from brownells when I take it apart I'll put my calipers on it.

[Lane]

First off; I'm pretty sure people are going to want a few pictures to help understand these problems...

3 hours ago, tapcaf said:

I can still a sliver of bolt lugs peeking out around the chamber lugs

This in particular sounds bad; but maybe you just mean you can see a sliver a of the bolt, and not the actual locking lugs? It should be reasonably apparent when the bolt is actually closed. Not a lot of substitutes for a real headspace check; but chambering a live round in a safe place, then checking the wear can't hurt in terms of function testing. Better still if you can make your own dummy round on a reloading press. If you can see the locking lugs; you can be reasonably sure the bolt isn't closing; and it's not safe to fire. I've included an image of mine; you can see on the right side that there is only a tiny gap between the bolt carrier and the edge of the ejection port in the upper. I can't see any significant part of the bolt, and certainly not the locking lugs.

3 hours ago, tapcaf said:

where the upper meets with the lower it is stopping my mag from entering the 10% of the way

It would also help to see parts of this as well, since there are a few things that could be going on here. I would first ask; does the magazine engage and release with the entire BCG removed from the upper? Is it actually the upper receiver itself that's causing this problem (I've never heard of that one myself)? I doubt the magazine insertion is related to the bolt catch based on what you said; but you weren't sure about that part being correct either. I would expect wear marks on the magazine somewhere from forcing it closed no matter what. What kind of magazines have you tried so far?

Your issues here may be directly related to mixing a PSA upper with a different lower. There is a possibility that the magazine catch on the lower isn't "correct" for use with the PSA upper. I'm not a PSA expert, but I'm sure some knowledgable people will be along shortly.

[tapcaf]

Sooooo I loaded a dummy round (case and bullet no primer/powder) now I got a little lazy I didn't take out the extractor or ejector of the bolt(i've always done that when headspaceing) I wanted to see what a good analog of a real round in the chamber would like......   OO HOLY poop

I think this is a barrel issue?? I find it hard to believe a different bolt would fix that much of an issue just a little over an 1/8 of an inch.  the second photo is the dummy in chamber I think it's sticking out too far and yes the barrel is marked 308 I got it out of an estate sale I was at, it was still pack in it factory box with packing grease and plastic dust covers.

 

 

[98Z5V]

Cutting the backside of bolt lugs is directly the wrong thing to do. You need to ream the chamber - it's short.

[98Z5V]

On 8/28/2019 at 10:36 PM, tapcaf said:

1. Headspace is at minimum possibly below what should a fully engaged lug look like. I can still a sliver of bolt lugs peeking out around the chamber lugs, I was able to get a 1/1000 feeler gauge nest to it about the same I was thinking about removing the coating off the bolt face to see if it will flush up.

You need headspace gauges, not feeler gauges.

[edgecrusher]

Can we have a complete parts list as well. There is a lot going on...

[tapcaf]

19 hours ago, edgecrusher said:

Can we have a complete parts list as well. There is a lot going on...

DPMS LR308

Upper: Palmetto state armory upper Gen1,  brownells bcg, 16" unmarked 308win 41v50 barrel, basic gas block,mid length  ss gas line, m lock quad rail, big honking muzzle break. ambi charger barrel nut forward assist dustcover (no name).

Lower: Tennessee arms 308 hybrid lower, brownells lower parts kit, tubs 308 carbine flat spring, H2 carbine weight, FAB defense GL-SHOCK CP  stock, 6 position buffer tube, extended mag release, push safety.  (Looking at tig welding a bad on to the catch)

spiffy bits: Fab Def Quick Release T-pod forward grip, 250 lumen tac light, 200 lumen IR light (lights up the forest with my goggles)

 

 

[98Z5V]

12 minutes ago, tapcaf said:

DPMS LR308

Upper: Palmetto state armory upper Gen1,  brownells bcg, 16" unmarked 308win 41v50 barrel, basic gas block,mid length  ss gas line, m lock quad rail, big honking muzzle break. ambi charger barrel nut forward assist dustcover (no name).

Lower: Tennessee arms 308 hybrid lower, brownells lower parts kit, tubs 308 carbine flat spring, H2 carbine weight, FAB defense GL-SHOCK CP  stock, 6 position buffer tube, extended mag release, push safety.  (Looking at tig welding a bad on to the catch)

spiffy bits: Fab Def Quick Release T-pod forward grip, 250 lumen tac light, 200 lumen IR light (lights up the forest with my goggles)

What you have listed for parts has nothing to do with a DPMS LR-308, in the least way. That might have been the base-platform for the configuration, but what you have listed is a trainwreck of parts.  Hope that doesn't hurt your feelings.  What you have listed for parts will take a whole day to go through, just to try to figure out what you have going on here, I'm not kidding.

Why don't you just start with the VERY specifics on that recoil system. INTERNAL DEPTH on that receiver extension (stick a tape measure down it, and see how deep it is - it's either 7.000" or it's 7 5.8" deep).  You state "H2 carbine weight" but what the hell is that?  What's the buffer LENGTH, and what's the exact weight of it?  If it's H2, I can tell you the weight of an H2 buffer  - but I want to know what YOUR buffer weighs, and how long it is...

Don't take this wrong - you have a whole mess of shiit going on. We'll get into the gas system after the recoil system, after your statement of "16" unmarked 308win 41v50 barrel, basic gas block,mid length  ss gas line..."   recoil system first, then we try to decipher your gas system.

[Cliff R]

Did you build the upper from "scratch" and add a barrel you purchased at an Estate sale? 

If so did you check the chamber to see if a round fully seated them easy to remove before putting it all together?

I'm up to 10 builds now and haven't had the first problem one with any barrels we've used.  I do have a drawer full of leftover parts figuring out interchange and compatibility issues between different variants.  BIG difference between a 308 AR platform and the AR-15 stuff, and the cloudy water is further muddied up if you spend much time on Google.  I was in that rut before finding this Forum.......FWIW....Cliff

 

[mrmackc]

Some people can come out of a rose garden with a stinking mess, which I see as ten gallons of cat shitt in a five gallon bucket, and expect to smell like Old Spice. IMHO

[tapcaf]

On 9/2/2019 at 1:41 AM, 98Z5V said:

INTERNAL DEPTH on that receiver extension

7 5/8

On 9/2/2019 at 1:41 AM, 98Z5V said:

What's the buffer LENGTH, and what's the exact weight of it? 

3 1/4   4.7oz

 

On 9/2/2019 at 1:41 AM, 98Z5V said:

Don't take this wrong - you have a whole mess of shiit going on

None taken.

On 9/2/2019 at 8:10 AM, Cliff R said:

f so did you check the chamber to see if a round fully seated them easy to remove before putting it all together

Didn't realize it was that common of an issue.

[98Z5V]

2 minutes ago, tapcaf said:

7 5/8

3 1/4   4.7oz

With a 7 5/8" internal depth extension, you should be running a 3.250" length buffer that's 5.4oz.  Close enough, with your 4.7oz, to ensure function.  You gas tube looks like it's the right length, even with the funky angles in the pic you posted.  Don't play with the recoil spring, since you're this far - put the Armalite EA1095 spring in it.  That way, you'll have a reliable recoil system, slightly light buffer - but it shouldn't cause you functional issues, with that spring.  Recoil system, check.  Done, for now.

You need to sort that headspace issue out, next. 

[98Z5V]

On 8/28/2019 at 10:36 PM, tapcaf said:

2.The other issue is where the upper meets with the lower it is stopping my mag from entering the 10% of the way, if I pull the pin hinge the upper mag locks in then close pin back in works fine cycled manually it with five snap caps. AS soon as I drop the mag no binding gravity pulls it out, can't put in another tried different mags same thing. it's hitting the upper been thinking just sand off a few layers with my dremel (upper is a P.S.A mk1 lower is a Tennnessee arms hybrid lower)

 

This is an issue, and it sound like the issue of trying to combine Armalie AR-10A platform parts with Armalite AR-10B parts.  Specifically, the differences between 10A and 10B uppers and lowers. Research the differences between the Armalite AR-10A and 10B platforms - there are vids on YT covering this.

Next, your PA-10 Gen 1 or mk1 as you say - was such a giant heap of shiit that they stopped making it on short order, and came up with their Gen 2 designs.  I can't tell you what the differences are, but there were TONS of problems with PSA Gen 1 PA-10 guns.  Too many to list, and too many for PSA to keep up with, so they just scrapped it and went right into Gen 2.  You might want to think about just throwing that upper straight in the trash, or recycling it for the aluminum weight, and starting with something else that works.  Not being harsh - being realistic.

Maybe we can get a PSA Rep on here to explain the differences between their first try, and their Gen 2 design...

 

 

 

Doubt it, though.

[tapcaf]

55 minutes ago, 98Z5V said:

You might want to think about just throwing that upper straight in the trash

I had that Idea in the back of my mind

[tapcaf]

UPDATE: Fixed the head space I just bought a new barrel head space is now in speck, new upper is in the mail , disassembled the old upper.

I've been trying to find the dia speck of a 308 bolt catch to see if that is the problem why it wont lock back.

 

Here is mine for reference.

 

[98Z5V]

We have a tread specifically on these bolt catches, and all their dimensions, but what you're measuring doesn't amount to much - measuring from the outside of the paddle to whatever - it's gonna give you anything meaningful.  Search out our thread on the measurements of these things.  

Edited September 8, 2019 by 98Z5V

[willbird]

On 9/4/2019 at 12:58 AM, 98Z5V said:

This is an issue, and it sound like the issue of trying to combine Armalie AR-10A platform parts with Armalite AR-10B parts.  Specifically, the differences between 10A and 10B uppers and lowers. Research the differences between the Armalite AR-10A and 10B platforms - there are vids on YT covering this.

Next, your PA-10 Gen 1 or mk1 as you say - was such a giant heap of shiit that they stopped making it on short order, and came up with their Gen 2 designs.  I can't tell you what the differences are, but there were TONS of problems with PSA Gen 1 PA-10 guns.  Too many to list, and too many for PSA to keep up with, so they just scrapped it and went right into Gen 2.  You might want to think about just throwing that upper straight in the trash, or recycling it for the aluminum weight, and starting with something else that works.  Not being harsh - being realistic.

Maybe we can get a PSA Rep on here to explain the differences between their first try, and their Gen 2 design...

 

 

 

Doubt it, though.

FWIW I used a Gen I stripped upper to build an upper for my PSA complete lower and it worked fine. IMHO the actual differences are cosmetic. The only reason I used it was because it was all that was avail from PSA, they had no Gen 2 avail other than complete uppers. That said they may have tightened tolerances or something between I and II that did not show up in my sample of 1.

Bill

[SimonSays]

5 hours ago, 98Z5V said:

We have a tread specifically on these bolt catches, and all their dimensions, but what you're measuring doesn't amount to much - measuring from the outside of the paddle to whatever - it's gonna give you anything meaningful.  Search out our thread on the measurements of these things.  

 

Here's the thread 98Z was talking about:

 

 

[98Z5V]

5 hours ago, SimonSays said:

 

Here's the thread 98Z was talking about:

 

 

Thank you, for linking that one!  

[tapcaf]

Sorry for radio silence work went nuts based on the photos  on the noted thread mine is short it's too big for a 15 but I think it's too small for my rifle. I'll pick up a new one from brownells.

Got a new barrel and upper from midway most issues  fixed.