POF .308 Feeding Issue (Long)

[fast_hand84]

As some here may know, I’m a firm believer in POF rifles (the flagship lineup...not their newer “budget” stuff), and I currently run a Revolution .308 that is the most accurate & reliable rifle I have ever owned. I have, however, heard of issues guys are having with the newer stuff, particularly stuff built after Frank’s untimely passing.
I ran into one of those issues at the range yesterday with a newer Revolution (Piston .308 16.5) that a buddy just purchased. I have picked this thing apart, luckily having my flawless Revolution (same specs) to compare & swap parts with. This thing is driving me crazy, so I’m hoping some of the experts here can help me out.

Side Note: the obvious answer is to just ship it back to POF, but I’m not the kind to just give up on an issue without exhausting every possible option. Also, the owner is a little paranoid, and is very reluctant to ship a black rifle, considering the current climate.

Sorry for the long intro, but now on to the issue. The gun is incredibly accurate (~ 1/2 MOA consistently with 178 ELD-X), but is having feeding issues, particularly with the first round out of the mag, and is wreaking havoc on the brass and bullet of any round that is chambered successfully. My first thought was a mag issue, but we were able to replicate the issue with 10,20,and 25 round Pmags, as well as my D&H SR-25 pattern 20 round mags (neon green follower), which I have tuned up to run smooth (corrected & polished feed lips), and the issue is present whether the mag is fully loaded, or only partially.

As I began troubleshooting, it became very obvious that the round is catching (hard) in between the lug recesses as it travels up the feed ramp. It seems as though the round is getting bound up between the feed ramp and the lip of the magazine...so as the feed ramp is trying to tilt the round up towards the chamber, the lip of the magazine is preventing it from doing so without a fight.

This is how the round is presented with the BCG back

And this is how the FTF goes

The magazine is properly seated, and the lips barely clear the BCG.
The feed ramps are fighting the magazine lips so bad that it actually bent the front of the lip of the D&H mag

This issue happens with both sides of the mag, both feed ramps. I ran a q-tip along both feed ramps to check for any burrs, but they seem smooth.

Something else I noticed (possibly unrelated) is that the cam pin is beating up the cam pin slot a lot more than I think it should, especially considering the rifle has POF’s roller cam pin, which is designed to mitigate that very thing.

I’m sure I am forgetting things, but I can provide any additional info or pics as needed. Thanks in advance for your help.

 

[bfoosh006]

Have you tried different ammo ?

Maybe the ogive on the 178gr is just off enough to cause the feeding issue ? ( Just a guess.... )

As for the Roller Cam pin... I'd keep an eye on that, the battering on inside of the upper isn't right.

And I would certainly adjust the gas lower.... the marks "imply" a vigorous cycling.

 

[fast_hand84]

Have you tried different ammo ?

Maybe the ogive on the 178gr is just off enough to cause the feeding issue ? ( Just a guess.... )

As for the Roller Cam pin... I'd keep an eye on that, the battering on inside of the upper isn't right.

And I would certainly adjust the gas lower.... the marks "imply" a vigorous cycling.

Ah, forgot to mention that the issue exists with various types of factory ammo, including Federal 180gr. soft points and Hornady’s 125 gr. reduced recoil loads. It seems to have an easier time feeding the soft points, though...I’m guessing that’s due to the shape. Thanks.

 

[S197]

Dose this happen if you run a partially loaded mag?

 

[fast_hand84]

Dose this happen if you run a partially loaded mag?

Sure does.

 

[S197]

Second question. how dose the mag seat when you insert it into the lower? dose it take any force to lock it in? Or is it loose?

 

[fast_hand84]

Second question. how dose the mag seat when you insert it into the lower? dose it take any force to lock it in? Or is it loose?

Doesn’t seem to require an unusual amount of force to get a mag to lock in as long as the bolt is open. However, it’s pretty tough to get a metal mag to seat if the bolt is closed, and damn near impossible to get a Pmag locked in when closed.

Once inserted, the mags don’t seem super tight though. You can rock it front to back without too much effort.

 

[KcConquistador]

My two cents on the roller cam pin is that it effectively applies a point force on the upper receiver where a standard cam pin applies the same force over the length of the cam pin head. I noticed this ‘damage’ in one of my AR-308 uppers that was working fine and went back to a standard cam pin. YMMV.

 

[S197]

Remove the upper and insert a loaded mag into the lower. We will need to check for clearance in two locations. The first location is where the bolt catch is. There should be no contact with the mag here. Next is where the mag locks into the lower. If it is tight here do the following for testing.

If you have a cheap toss away mag, slowly remove material from the bottom of the locking port on the magazine body. If you don’t have a cheap mag, remove the latch and inspect it.

if the above clears your problem, then I would pull the mag lock from the lower and remove any burs or casting lines from the material.

 

[fast_hand84]

Remove the upper and insert a loaded mag into the lower. We will need to check for clearance in two locations. The first location is where the bolt catch is. There should be no contact with the mag here. Next is where the mag locks into the lower. If it is tight here do the following for testing.

If you have a cheap toss away mag, slowly remove material from the bottom of the locking port on the magazine body. If you don’t have a cheap mag, remove the latch and inspect it.

if the above clears your problem, then I would pull the mag lock from the lower and remove any burs or casting lines from the material.

Thanks for the suggestion. I will give it a shot tonight and report back.

 

[S197]

What gen pmags are you using? POF tech states only to run gen 3 pmags or lancer l7awm mags with anti-tilt followers in their 308 rifles.

 

[bfoosh006]

What gen pmags are you using? POF tech states only to run gen 3 pmags or lancer l7awm mags with anti-tilt followers in their 308 rifles.

Interesting... I was not aware of that.

 

[fast_hand84]

What gen pmags are you using? POF tech states only to run gen 3 pmags or lancer l7awm mags with anti-tilt followers in their 308 rifles.

Sorry about the delayed response; I got tied up at work, but I do have some updates I discovered early this AM. And before I forget, yes, all Pmags used for testing are G3.

With the upper removed, it doesn’t change the effort required to seat any of the mags.

I am still thinking the issue arises when the round binds up between the forward end of the mag lip (holding the case down), and the feed ramp (forcing the nose of the bullet up, simultaneously). Last night I took a file (and some other shit) to two of the PMags (and one of the steel mags) in an attempt to correct the angle at which the magazine presents the round to the gun. The results are an initial success, as far as reliability in feeding goes.

The unmodified mag is in the center.

The gun is feeding reliably at home now, but this fix seems like a band-aid, representative of another issue. I’m heading to the range tomorrow, so I will report back.

 

[fast_hand84]

Was able to hit the range today (only 100 yards), and the rifle ran great with the modified mags...only one hiccup, which I’ll address later. The nature of that success, however, (running on modified mags) leaves me suspicious of an underlying issue.

Also, I’ve got the gas block turned as low as possible (without making it into a bolt gun), and I’m still overgassed on the hotter/heavier loads. The buffer spring is supposedly some proprietary shit, but I’m thinking about adding a heavier buffer to slow the gun down a little. Stock weight is 3.2 oz , IRC...any suggestions will be appreciated.

 

[smoothy8500]

You can buy a set of Tungsten buffer weights on Amazon or eBay for around $25 shipped. I know a few guys that played around with adding 1 or two in the buffer. I changed out 1 in my 308 A2 rifle buffer.

 

[fast_hand84]

You can buy a set of Tungsten buffer weights on Amazon or eBay for around $25 shipped. I know a few guys that played around with adding 1 or two in the buffer. I changed out 1 in my 308 A2 rifle buffer.

Thanks man. I’ll give it a shot.

 

[S197]

Have you tried removing the magazine catch to inspect it? Also while it is out insert a mag and check for resistances.

 

[BCP]

I had the same problem the mag was sitting a tiny bit too low. Cutting the mag lips back so the rounds feed easier is one way to solve it another way is to cut in some extended M4 type feedramps. My DPMS SASS didn't have them from the factor. I honestly don't remember if my POF 308 had the extended feed ramps tbh.

 

[Rideandshoot]

Have you solved the feed issues on your 308 Revolution? I had my Revolution DI Pistol 308 out yesterday and it started to fail to feed and fail to eject after about 20 rds. Kept getting worse, occurring on first round of the pmag and then the last time it wouldn't even eject and the bcg was jammed. Destroyed a bunch of rounds. Used Hornady and Nosler. I also shaved the lips of the mag a bit with a knife in order to allow the rds to sit higher. That didn't help. I had my gas at the second setting, but switched to the third because I was ejecting to four thirty or so. I am amazed this is happening at 20 rds or so. I haven't taken it apart yet to clean and maybe polish the fees ramps. I also wonder if my ejector spring is working correctly.

Just curious if you did anything else besides working on the mag.

Thanks

 

[RUTGERS95]

I don't what has happened to pof but all I see on boards over past few yrs is issues or rather, more being vocalized. I had an older pof that was pretty accurate and liked it but sold it.

 

[person]

Also try Hex mags, I've been using them in my Rogue and it's been fine.

 

[BamaSE]

FWIW….one of my night hunting buddies and I acquired the Revolution at the same time a while back. DI version and both suppressed. Both started out using 178 grain ELD-Xs. And yes highly accurate in this rifle. Both had similar feeding issues. I ran a couple hundred rounds of mixed hunting and FMJ ammo through mine and it got much better. Finally got the gas blocked dialed in right after all this too. I am not a gun tech guy so all I know is is worked…but not why! I wound up swapping to Nosler 165 grain Accubonds as that is what I run in my other .308s. No issues at all since. He is still running the ELDs and still has similar issues to yours. He has held off running a lot of ammo thru it given the shortage so I cannot report yet if doing that is replicated in his.

 

[LRRPF52]

The cartridge stack sits at different heights depending on the feed lip thickness, which is most noticeable between polymer and metal feed lips.

Try the problem rifle upper with the no-problem rifle lower and see if it does it still. That will tell you if the problem is with the lower.

Also, do what has been recommended at least twice now and inspect the magazine catch.

My knee-jerk response is that something is off with the cartridge stack height in the problem gun.

There are 7.62 NATO PMAGs that work in some 7.62 ARs, then won’t work in others based on which Generation the company used to set their mag catch location.

I have seen problems go away with several .308 ARs that had feeding problems with PMAGs when we switched to Lancers.

My personal large frame ARs have always run fine with 1st Gen 7.62 NATO PMAGs.

 

[Ape_Factory]

I'll have to check which gen PMAGS I'm using but I believe they're all gen 3. I purchased my Revolution DI in spring of 2020 and I've literally never had a failure to feed issue with any ammo I've used. POF says to use only gen 3's or Lancer L7AWM mags, both which have anti-tilt followers. Others will give you issues.

 

[RUTGERS95]

The cartridge stack sits at different heights depending on the feed lip thickness, which is most noticeable between polymer and metal feed lips.

Try the problem rifle upper with the no-problem rifle lower and see if it does it still. That will tell you if the problem is with the lower.

Also, do what has been recommended at least twice now and inspect the magazine catch.

My knee-jerk response is that something is off with the cartridge stack height in the problem gun.

There are 7.62 NATO PMAGs that work in some 7.62 ARs, then won’t work in others based on which Generation the company used to set their mag catch location.

I have seen problems go away with several .308 ARs that had feeding problems with PMAGs when we switched to Lancers.

My personal large frame ARs have always run fine with 1st Gen 7.62 NATO PMAGs.

great post, agree on the 1st gen mags as they seem to work in my 308s without issue.

Hex Mags can be tight in some wells and free in others I've found

Still my go to mag are the D&H mags as I've yet to encounter a single issue with them feeding or otherwise. Plus I like metal better

 

[Rideandshoot]

I am having the exact same FTF issues on the initial round and also during firing of my POF Revolution 308 AR Pistol. I haven't figured it out am having every single round not make it into the chamber with a bcg over ride. I have once, in the field while camping, tried to file the Gen3 Pmags lips to present a higher stack as I agree, for some mechanical reason, the rounds are not high enough or tilted correctly to be picked up by the bcg and properly chambered. I am going to try better filing of the mag lips now that I am home.

 

[Rideandshoot]

I just filed the lips of a 20 round pmag and was able to chamber five 1st rounds successfully. Before finishing the filing, I still couldn't get first round clambering from any of the pmags. I'll see tomorrow how it cycles while firing. If someone is using metal mags, just bend the lips up some until it feeds well. These lip adjusted magazines may not work as well in other AR10s.

 

[GreenGO Juan]

I had to file the mags as well. How I approached it was pushing the mag up into the well and holding it there while cycling the bolt until it would no longer bind on the lips of the mag. The bolt will leave witness marks on the plastic mag. File these out until it stops. Used a dummy round(no primer or powder) to do this. Take percautions if u use live rnds.


I also filed a 45 on the front to allow to neck of the cartridge to pass more easily over the front lip of the magazine. I noticed this was another bind point when pushing round with my fingers . Manually push the rounds out of the mags and see if they stick here, i found this another bind point.



Took this pic for reference. You can see how the lugs on the bolt face can catch the lips on the mag.
Another thing, make sure this nylon adjustment screw is as far out as it can be while still able to insert the take down pin. Doing this keeps upper and lower from moving in relation to each other. I check this every time I open it up.

Another thing i did was lightly lubed, with white grease, the 3 grooves inside the mag so it moved smoother.

Doing these things helped it run smoother.

Definitely a point of frustration. Not sure if its a magpul issue or a pof machining tolerance issue?!? But seems many are experiencing this. Filing the mag in two places and lubing the 3 slots in the mag did help my situation. Keeping the nylon tension between the upper and lower removes play and keeps the bolt in line when coming out of the buffer tube. But for the pr.. this should not be a issue.

Have not tried lancer mags.

 

[fast_hand84]

View attachment 7668845
I had to file the mags as well. How I approached it was pushing the mag up into the well and holding it there while cycling the bolt until it would no longer bind on the lips of the mag. The bolt will leave witness marks on the plastic mag. File these out until it stops. Used a dummy round(no primer or powder) to do this. Take percautions if u use live rnds.

View attachment 7668844
I also filed a 45 on the front to allow to neck of the cartridge to pass more easily over the front lip of the magazine. I noticed this was another bind point when pushing round with my fingers . Manually push the rounds out of the mags and see if they stick here, i found this another bind point.

View attachment 7668842

Took this pic for reference. You can see how the lugs on the bolt face can catch the lips on the mag. View attachment 7668843
Another thing, make sure this nylon adjustment screw is as far out as it can be while still able to insert the take down pin. Doing this keeps upper and lower from moving in relation to each other. I check this every time I open it up.
View attachment 7668851
Another thing i did was lightly lubed, with white grease, the 3 grooves inside the mag so it moved smoother.

Doing these things helped it run smoother.

Definitely a point of frustration. Not sure if its a magpul issue or a pof machining tolerance issue?!? But seems many are experiencing this. Filing the mag in two places and lubing the 3 slots in the mag did help my situation. Keeping the nylon tension between the upper and lower removes play and keeps the bolt in line when coming out of the buffer tube. But for the pr.. this should not be a issue.

Have not tried lancer mags.

Not a Magpul issue, unfortunately, as mine does it with mags from various mfgs, both plastic and metal.

 

[Rideandshoot]

View attachment 7668845
I had to file the mags as well. How I approached it was pushing the mag up into the well and holding it there while cycling the bolt until it would no longer bind on the lips of the mag. The bolt will leave witness marks on the plastic mag. File these out until it stops. Used a dummy round(no primer or powder) to do this. Take percautions if u use live rnds.

View attachment 7668844
I also filed a 45 on the front to allow to neck of the cartridge to pass more easily over the front lip of the magazine. I noticed this was another bind point when pushing round with my fingers . Manually push the rounds out of the mags and see if they stick here, i found this another bind point.

View attachment 7668842

Took this pic for reference. You can see how the lugs on the bolt face can catch the lips on the mag. View attachment 7668843
Another thing, make sure this nylon adjustment screw is as far out as it can be while still able to insert the take down pin. Doing this keeps upper and lower from moving in relation to each other. I check this every time I open it up.
View attachment 7668851
Another thing i did was lightly lubed, with white grease, the 3 grooves inside the mag so it moved smoother.

Doing these things helped it run smoother.

Definitely a point of frustration. Not sure if its a magpul issue or a pof machining tolerance issue?!? But seems many are experiencing this. Filing the mag in two places and lubing the 3 slots in the mag did help my situation. Keeping the nylon tension between the upper and lower removes play and keeps the bolt in line when coming out of the buffer tube. But for the pr.. this should not be a issue.

Have not tried lancer mags.

Yes, my cartridge pickup became smoother and quieter once I filed enough off on the sides. I will also file the front. Thanks.

 

[alexander66]

I had a similar problem with my POF build from a reputable builder, sent the rifle back twice, they could not find a problem with the rifle. I ran this rifle suppressed also. The rifle would run good for one mag then the FTE/FTF would start. I changed mags the problem persisted. So I was stuck with a $4,000.00 in this rifle. For me I did not want to modify feed rams or magazines. I randomly decided to change my gas rings over to enhance rings and all of my problem went away. So 1500 rounds later the rifle is flawless suppressed or un-suppressed.

 

[Rideandshoot]

I had a similar problem with my POF build from a reputable builder, sent the rifle back twice, they could not find a problem with the rifle. I ran this rifle suppressed also. The rifle would run good for one mag then the FTE/FTF would start. I changed mags the problem persisted. So I was stuck with a $4,000.00 in this rifle. For me I did not want to modify feed rams or magazines. I randomly decided to change my gas rings over to enhance rings and all of my problem went away. So 1500 rounds later the rifle is flawless suppressed or un-suppressed.

We're you getting random ejection patterns?

 

[alexander66]

Yes, the ejection patterns random.

 

[samnev]

This may be apples and oranges but I've been using 1st and 2nd GEN 20 round Pmags in my 2010 built P-308 and never had a single feeding issue. Perhaps the Gen 3 warning only applies to newer 308 POF's.

 

[GreenGO Juan]

I have 5 Gen3 Pmags mags. When new they would all occasionally jam up on the bolt lugs as described above, a minor file/sand, they work well. I have around 1700 rounds through mine which is a CMR Rev and has 2020 and 2021 manufacture stamps on the parts.