GAP -10 Failure to Feed/Eject

[tiNdvenTFHwMdqKW]

GAP-10's are like tight young virgins. They usually need to be "broken in". The breaking in isn't always "awesome" but if done right the results should be close to perfection.



Take that bitch out and work her.

 

[LRRPF52]

My GAP .260 Rem never needed break-in, but I have only run hand loads through it, ranging from 95gr-142gr bullets. The only time I have been able to get it to choke is shooting from a closed ejection port cover. My suspicion is that the AR10 needs a stronger ejection port spring to prevent partially open port door deflection during ejection from closed door condition.

 

[Gunfighter14e2]

Interesting, I've a box stock POS DPMS 16" LR308 and it eats and shits out everything it's been fed to date. If I'd paid that much for a gas gun and was told it had to eat XXX ammo only to operate correctly I'd be questioning my sanity about buying it in the first place. Loved the comments about not being proper ammo, guess if it goes to shit and that weapon has to be used for protection the buy was a waste in the first place Uh? There is much B/S in this thread, Call GAP and they will fix it. That POS should eat every kind factory .308 ammo made, w/o issue. When factory's load ammo it is loaded to shoot and operate every type of weapon that is chambered in that cal, if there is exceptions they are plainly listed. Some of you guys are talking out you ass because your month knows better. The Internet were you can read and be an expert the same minute.

 

[Captain Kirk]

Interesting, I've a box stock POS DPMS 16" LR308 and it eats and shits out everything it's been fed to date. If I'd paid that much for a gas gun and was told it had to eat XXX ammo only to operate correctly I'd be questioning my sanity about buying it in the first place. Loved the comments about not being proper ammo, guess if it goes to shit and that weapon has to be used for protection the buy was a waste in the first place Uh? There is much B/S in this thread, Call GAP and they will fix it. That POS should eat every kind factory .308 ammo made, w/o issue. When factory's load ammo it is loaded to shoot and operate every type of weapon that is chambered in that cal, if there is exceptions they are plainly listed. Some of you guys are talking out you ass because your month knows better. The Internet were you can read and be an expert the same minute.

Well, there may be a issue with the rifle, I agree with you there. Not sure why you feel the need to try and ridicule everyone that is trying to help the OP, or think it is uncommon or unacceptable for something to have a issue. I call it armchair diagnostics, we can't accurately determine what the issue is on the internet, but many (not all) have had failure issues and worked through them, some may be valuable input and some may not. Does DPMS have a 0% failure rate? Toyota? Chevy? Things happen, the silver lining here is GAP has a golden reputation of how they handle issues, which do happen.

 

[Gunfighter14e2]

Well, there may be a issue with the rifle, I agree with you there. Not sure why you feel the need to try and ridicule everyone that is trying to help the OP, or think it is uncommon or unacceptable for something to have a issue. I call it armchair diagnostics, we can't accurately determine what the issue is on the internet, but many (not all) have had failure issues and worked through them, some may be valuable input and some may not. Does DPMS have a 0% failure rate? Toyota? Chevy? Things happen, the silver lining here is GAP has a golden reputation of how they handle issues, which do happen.

Anything man made will fail, why I said call GAP, but to tell someone it has to have XXX ammo to run correctly is outright internet bullshit. It may not group as good w/ XXX over YYY but the POS should still go bang every-time until the mag is empty,...

 

[Hoax001]

I had similar issues with my high end AR10. It worked perfect only after about 200 rds and lubing the hell out of it. They just come from the factory too tight and need a break in or wear down some of the surfaces and edges that are too tight. And lubricating by taking apart the entire BCG and lubing all the sliding surfaces. Mine will shoot any 308 or 7.62x51 round but I just use match now.

Also sometimes mags will cause issues. I did not see this mentioned yet. Have you inspected your mag follower? Can you try different mag manufacturers? Does the bolt lock to the rear after you fire the last shot?

Also, have you switched out the stock? I didnt see this mentioned either. It is common for people to get these issues after changing the stock but not changing to the correct buffer system.

All great suggestions. I am going out to the range tomorrow and will check the magazine, stock, etc. Thank you for your suggestions.

 

[FCS]

Interesting, I've a box stock POS DPMS 16" LR308 and it eats and shits out everything it's been fed to date. If I'd paid that much for a gas gun and was told it had to eat XXX ammo only to operate correctly I'd be questioning my sanity about buying it in the first place. Loved the comments about not being proper ammo, guess if it goes to shit and that weapon has to be used for protection the buy was a waste in the first place Uh? There is much B/S in this thread, Call GAP and they will fix it. That POS should eat every kind factory .308 ammo made, w/o issue. When factory's load ammo it is loaded to shoot and operate every type of weapon that is chambered in that cal, if there is exceptions they are plainly listed. Some of you guys are talking out you ass because your month knows better. The Internet were you can read and be an expert the same minute.

Somebody here is talking out their ass and their mouth. Box stock POS DPMS is a fine battle rifle to eat any and all 308 ammo. GAP-10 is a precision instrument, it is in fact tuned to specific ammo. Sounds to me like you are not a GAP-10 kinda guy, nothing wrong with that. Some guys like performance sports cars, some like commuter cars, some like pickup trucks and some like to have one of each in the stable to pick right tool for the job.

Anything man made will fail, why I said call GAP, but to tell someone it has to have XXX ammo to run correctly is outright internet bullshit. It may not group as good w/ XXX over YYY but the POS should still go bang every-time until the mag is empty,...

No sir, no internet bullshit in saying that GAP-10 has to have XXX ammo to run correctly. Unfortunately you are the one spreading opinion, conjecture and misinformation (a.k.a. outright internet bullshit to borrow your phrase).

This rifle came back because the dept used 155 Hornady TAP. It's a light load. And the rifle had to be tuned to it. It ran other ammo fine.


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That's actually not always the case , M118LR was originally made and speced for bolt rifles. The USMC and then the Army made a ton of changes over a long period of time to get it to work well in the Mk11 and M110. I know this as when the guys were in town working with Lake City. They stopped by the shop a lot. The Navy also has special lots and designations for Gas gun ammo. IE Mk 216. At any rate if someone has problems with M118LR in a gas rifle it's a well documented issue. With a gas rifle you have to find ammo that will run in the rifle or load to the rifle like the OP is doing and sharing with you all. Equate it to the need for Premium pump gas in a Vette, 87 won't Run it. ?


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You will be fine, start with new brass if reloading or invest in Small base dies which will return fired brass to new size. There are about 700 GAP-10's out there lots of PD's have them. They run just fine when fed the right diet!



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[Gunfighter14e2]

The Cool-aid must be strong in your world, and that's fine. Keep believing money and looks will win a match or gun fight, but history proves and has proved otherwise. When buying any gun made, if the stars have to be aligned for it to go bang, either quality or design is lacking. I've owned most every type of match gun (hand & long)made in my lifetime, not a one had to have XXX ammo to go bang. Most shot better with certain loading, but even with the worst shit on the market, "They ALL WENT BANG". Keep drinking the cool-aid w/o question, seems to work for you.
John Browning, Elmer Kieth, Bill Ruger, and a few others were ask about ammo specific, semi auto weapon designs. Search(or not)what they had to say about that simple fact when talking group size vs fitment and going bang.

 

[FCS]

Understanding the parameters of a specific system is not about drinking the cool-aid, it is about knowledge. You seem to be confusing knowledge of a specific system with opinion of how something should be, maybe you need to lay off the cool-aid. Never did I say it should be a certain way, or it shouldn't be a certain way. I did say these are the parameters around which a GAP-10 was designed and that as a purpose built system the ammo required for reliable operation falls into a specific window. Clearly the OPs rifle is not behaving and there can be any # of possible causes: ammunition (which OP has tried changing), rifle needs to break in, or there is a gas system issue. Even with the gas system fixed (if it is a gas system issue), I don't believe a GAP-10 is going to run any and all 308 ammo, 110 gr to 190 gr, that is on the market.

GAP-10s have a different design intent, operating parameters. You don't buy a sports car to go down to the lumber yard to pick up sheets of sheetrock.

I ask a lot of questions, I do a lot of experimenting, I gain an understanding of how the system works. You may or may not do that. I define the parameters of what I need a system to do, then I buy (if available) or build the system to run within those parameters.

 

[dmike]

Anything man made will fail, why I said call GAP, but to tell someone it has to have XXX ammo to run correctly is outright internet bullshit. It may not group as good w/ XXX over YYY but the POS should still go bang every-time until the mag is empty,...

I see your point but do you think that different pressure curves affect gas systems differently? My p308 was cycling fine but unbeknownst to me I was, um, tuning up my op rod. I think some folks are just saying the gaps gas system is fine-tuned for a specific pressure curve/level. Using the least amount of force necessary to cycle, for maximum accuracy. You could open it up to slam the carrier back but it might be hard on components and accuracy.


Btw you've got me thinking about a dpms!

 

[Shoottothrill]

Hoax if that Gap 10 doesn't run like a sewing machine after a couple hundred rounds send it back to Gap and have them fix it, send all your ammo receipts and ask them to reimburse you, if its their fault they should.

Did Gap install your Gas block, or did you or someone else do it?

 

[BCP]

OP you paid a lot of money for that rifle, probably waited a long time too, call GAP and see what they think before you spend any more money on ammo or range trips.

As I mentioned, I have the Precision Reflex low profile adjustable gas block. The gun smith (who is a competition shooter) is convinced this is a gas issue.

WTF? How did that get on there? If it came from GAP with a different gas block I would put the old one back on. Otherwise you need to dial it up as it sounds like obvious short stroking.

The Cool-aid must be strong in your world

It's kool-aid.

I agree with you that he needs to send it back to GAP. Everything else you posted was just asinine bullshit.

 

[Gunfighter14e2]

I agree with you that he needs to send it back to GAP. Everything else you posted was just asinine bullshit.

About like paying that much for a product that will not function, bet you ass thats bullshit. Now if it's something out of their(gap)control it falls on the user, but to buy a Corvette and have it stumble from the line is horseshit. A gun has to go bang to be worth a shit, if your looking for greatness on target that only works when it wants to, you win!
With today's metal and machining ability (at the product price point) easy to say it needs to break in, but most that know don't buy that. For the amount of wait time an money spent why should the end user have to complete the build by breaking it in, for it to just go bang each time the trigger is pulled?

 

[FCS]

To finish first, first you must finish. No argument there.

I've loaded for a fair number of GAP-10s, never had an issue. 6 Creed and 308 mainly. Possible this is an issue from GAP, if it is I'm certain they will take care of it. However, rifle was test fired and functioned from the GAP so find out what that ammo was, get some and see if it rifle functions. If rifle does not function, then clearly something is amiss and it would lead towards GAP needing to do a corrective action. If rifle does function, then you can't blame the 'Vette for stumbling out of the gate when the wrong fuel was put in the tank.

I've built my own custom ARs, we'll keep this to 308 for now, that I geared specifically to run 175 SMKs. Drop dead reliable, system designed to run exact same load as my bolt rifle and it does that w/o tearing up brass. I also found that in that system 155s or lighter are only about 90% reliable, get an occasional failure to function properly. 168 SMK, 175 SMK, 190 SMK the rifle runs like a top. Will rifle cycle every possible 308 round? No, it has some pretty specific boundaries. I expect the GAP-10 does also. I personally wanted to extract every bit of accuracy I could from my AR build, not tear up brass, shoot same/VERY, VERY similar load as my bolt rifle and have 100% reliability within a specific bullet/load range. I get at/below 0.5 MOA on routine basis, brass looks like it came from a bolt rifle, 100% reliability; I met my design criteria. I also control what ammo goes into that rifle. I suspect the reason people buy a GAP-10 is for the very same reasons: extract every bit of possible accuracy, not tear up brass and shoot a very similar load to what they can run from their bolt rifles and get bolt gun like accuracy.

Based on data I've gathered from building 308 ARs to my personal specifications/requirements, not practical to expect a 147 FMJ load to cycle a gas system optimized around a 175 SMK load. I loaded the 147s with a different powder then what is normally going to be found in mil-spec 147 ammo, specifically to see if I could get reliable functioning; I did not get reliable functioning with that 147 ammo. Port pressure, gas volume not matched well. Most 147 FMJ is geared to be compatible with M1A or similar gas system, that is a lower port pressure and gas volume system then what a large frame AR specifically tuned to run 175 SMK ammo is going to want to see for reliable function. What I've seen from factory 308 ARs is that they are geared to run 147 FMJ (Win white box, AE, mil surp) or similar. Feed those rifles 168 / 175 gr match ammo and brass is pretty much one n done as there is a huge burr on case head from rifle extracting under pressure because gas port is too large. Primer pockets get stretched out and half cases won't hold a primer afterwards, if case will will hold primer it is going to leak upon next firing which is going to give you less then stellar accuracy. What the heck, it went bag every time, cycled and shot 1 MOA or so. But, but I can put on an adjustable gas block and fix the problem...yeah, kinda sorta but not really. Played that game with factory 308 ARs before I built a rifle to my specs. Once the port is too large you can make corrective issues but that is never as good as having the port sized correctly in the first place. Okay, that is an opinion on port size and not fact.

OP tried 147 FMJ PMC ammo, has since switched to 175 with better performance but not functional. How dirty is PMC 147 ammo? I've never shot PMC 147 ammo so I really do not have any feel for how clean/dirty that powder used is. How much did the PMC 147 ammo gunk up the gas system, foul port, etc. Maybe GAP needs to specify what they have found to be functional ammo in a GAP-10, provide a known ammo list for end users. Maybe customers needs to let GAP know exactly what ammo they plan to use in the GAP-10 so rifle can be tuned for that ammo.

Does GAP have a 100%, every rifle perfect out of the gate track record? I do not know answer to that but I'd have to say no as mathematically, statistically it is all but an impossibility given that all it takes is a single event to drop you below 100%. George already stated he fixed a GAP-10 that they wanted to run 155 Amax ammo in, so I guess I do know it is not 100% yield rate right out of the gate. I suspect it is in mid to high 90% rate as we are all human and sometimes things slip through the cracks that shouldn't have. I also suspect that GAP fixes stuff that isn't really their fault but cheaper, easier to just fix and carry on.

 

[1Sg (ret)]

What makes you think it is getting too much gas as opposed to too little?

I have never seen one that wasnt over gassed unless you drill the gashole a little at a time till its just right.especially on a factory barrels.Adjustable gas blocks are the way to go.If you are shooting suppressed adjustable gas blocks are a must in my opinion.

 

[wareagle700]

I have never seen one that wasnt over gassed unless you drill the gashole a little at a time till its just right.especially on a factory barrels.Adjustable gas blocks are the way to go.If you are shooting suppressed adjustable gas blocks are a must in my opinion.

I agree most factory barrels are over gassed. However, this isn't a factory barrel, it has an adjustable gas block, and the issues the OP describes do not line up with what most people experience with an over gassed barrel.

 

[Hoax001]

Bolt not locking

Keep trying GAP, they will handle it. One thing to try is to load 1 round in the mag, fire it and see if the bolt locks open every time. This will tell you if the bolt is traveling rearward far enough, if it is "short stroking" it will fail to lock the bolt open on a empty mag or fail to scoop a round out of the mag.

I have tried every type of match ammo I can get a hold of. The bolt does not lock back. Rounds are jammed every single time now. I have cleaned the gun.

 

[Bird of Prey]

You can buy Federal GMM 168gr BTHP for $18.59/box right now. 308 winchester ammo rifle Federal 168 grains

That's not FGMM, its M1A OTM.

 

[Hoax001]

Thanks

 

[1Sg (ret)]

I agree most factory barrels are over gassed. However, this isn't a factory barrel, it has an adjustable gas block, and the issues the OP describes do not line up with what most people experience with an over gassed barrel.

Maybe i missed something.He stated it didnt have an adj gas block when he started the thread.

 

[wareagle700]

Maybe i missed something.He stated it didnt have an adj gas block when he started the thread.

My bad, you are right. Looks like he was using a Badger gas block to start with. I still don't think his problem is too much gas though, we will see.

 

[FCS]

Thank you. I did not go for the Noveske gas block, since I will be running it with a can most of the time. I opted for the Precision Reflex low profile adjustable gas block. It arrived yesterday and I will install it when my can gets out of jail.

Stats:
Geiselle SSA-E Trigger
Bartlein 18" 1-11.25 Twist with 5/8x24 Threaded Barrel
Badger MK12 Gass Block
Magpul PRS Stock FDE

Thanks for your help.

You didn't happen to tell GAP that you would be running a can most of the time yet you went with a standard gas block did you? GAP setup gas port around suppressed operation, standard gas block?

Regardless, I'd say it is time to talk to Kenny or Dustin, get a return trip scheduled for a tune up.

 

[smaw]

I have been in your shoes man. I know its frustrating. So the bolt doesnt lock back.

Can you lock it back by using your charging handle without firing a round? If not then you might have the wrong buffer, spring, or buffer tube or a bad combination of them. The buffer may be too long or the spring too many coils or too stiff or the buffer tube too short. I hate to admit it but this happened to me once. If this is the situation then measure them and count the coils and let us know what lengths they are.

Or is it only the case of firing of the last round and it not locking back on a empty mag? Maybe your buffer is too heavy. What does it weigh?

Also what stock do you have on it? Did it come with the Magpul PRS, Vltor, M16A2, what does it have? Different stocks use different buffer tubes, different buffers, different springs.

 

[Hoax001]

I have been in your shoes man. I know its frustrating. So the bolt doesnt lock back.

Can you lock it back by using your charging handle without firing a round? If not then you might have the wrong buffer, spring, or buffer tube or a bad combination of them. The buffer may be too long or the spring too many coils or too stiff or the buffer tube too short. I hate to admit it but this happened to me once. If this is the situation then measure them and count the coils and let us know what lengths they are.

Or is it only the case of firing of the last round and it not locking back on a empty mag? Maybe your buffer is too heavy. What does it weigh?

Also what stock do you have on it? Did it come with the Magpul PRS, Vltor, M16A2, what does it have? Different stocks use different buffer tubes, different buffers, different springs.

Thanks. I have the Magpul prs stock. I will check about the charging handle and how much the buffer tube weighs, spring etc.. and let you know. I appreciate the input.

 

[dmike]

Did it come with the prs or did you add it? I created issues with a gap by 'upgrading' to the wrong prs (ar15 will fit but won't work correctly)

 

[Hoax001]

Did it come with the prs or did you add it? I created issues with a gap by 'upgrading' to the wrong prs (ar15 will fit but won't work correctly)

It came with the prs stock.

 

[alexander66]

I gave my Gap 10 a good cleaning and lube when I first got it before shooting the rifle. Initially I had no issues, till after 20 rounds. I had problems with FTE and FTF, suppressed and unsuppressed. I am running the Noveske gas block. Call GA Precision, my problem was bad gas rings, that I corrected myself without sending the rifle back; it was an easy fix for me. You can spend a lot of time and money training to fix this issue when it could be something simple like gas rings; I zero issues after I changed my gas rings.

 

[Gunfighter14e2]

I gave my Gap 10 a good cleaning and lube when I first got it before shooting the rifle. Initially I had no issues, till after 20 rounds. I had problems with FTE and FTF, suppressed and unsuppressed. I am running the Noveske gas block. Call GA Precision, my problem was bad gas rings, that I corrected myself without sending the rifle back; it was an easy fix for me. You can spend a lot of time and money training to fix this issue when it could be something simple like gas rings; I zero issues after I changed my gas rings.

Please explain why you had bad gas rings, on a weapon that only had 20 rds thru it.

 

[Chance]

I had one that was overgassed. We put a SLR adjustable gas block on and it fixed the problem.

 

[alexander66]

Gunfighter14e2 - With my rifle the trouble started after 20 rounds, I tried different ammunition, running the rifle wet, running it dry, then I ran a different BCG and the problem stop. After a more detail inspection of my original bolt I isolated the problem to the gas rings. If I stood the BCG on end the bolt would not support it's own weight, once I changed the rings the bolt would stay full extended with the full weight of the BCG. It could have been a manufacturing defect with the gas rings; that is the only explanation I can think of, and then to fail after so few rounds. I have several thousand rounds through the rifle now with no issues at all. I have 4 AR 10's and my go to AR 10 is the GAP 10. Yes, I will buy another GAP 10. Best advise, if you are still having problems is to call GAP.

 

[Gunfighter14e2]

Gunfighter14e2 - With my rifle the trouble started after 20 rounds, I tried different ammunition, running the rifle wet, running it dry, then I ran a different BCG and the problem stop. After a more detail inspection of my original bolt I isolated the problem to the gas rings. If I stood the BCG on end the bolt would not support it's own weight, once I changed the rings the bolt would stay full extended with the full weight of the BCG. It could have been a manufacturing defect with the gas rings; that is the only explanation I can think of, and then to fail after so few rounds. I have several thousand rounds through the rifle now with no issues at all. I have 4 AR 10's and my go to AR 10 is the GAP 10. Yes, I will buy another GAP 10. Best advise, if you are still having problems is to call GAP.

I guess my question is this, why did they not find the issue before it was shipped to you? For the kind of money they charge (I've had two gaps) there should have been no issues at all. Both of mine were bolts and I will never buy, another anything, from them. Once both were rebarrel'ed by no name smiths they both shot like they should. Interesting about the gas rings as I have/had a few AR10's/15's an 16's in NFA trim, and many would never support the BCG, but ran in semi an full auto w/o issue?

 

[Detroit_1]

I have been under the impression that the weight of the BC invalidated the ‘ring test’ of extending it and standing it up on the Bolt. What replacement rings did you use out of curiosity? DPMS? / McFarland? / other?

 

[alexander66]

I was definitely not in a good mood when I started having my rifle issues after spending that much for the rifle and the wait to get it. I followed up with all of the normal recommendations, to include different ammo, I even made changes to my reloads to no avail. I used McFarland gas rings; the bolt could not stay extended with the bolt end up, the bolt would not stay extended with it's own weight. Installed the new McFarland gas rings and my issues when away. The rifle runs with just about any standard ammo that I feed it now, suppressed or on-suppressed (I don't even try any of the junk stuff).

 

[Detroit_1]

Alexander66 - thank you for the response. Again out of curiosity - did you install the McFarland ring or the JP Enhanced One Piece ring? I have read that the JP ring’s external dimension is slightly smaller than the McFarland - this is why I ask.

TIA

 

[alexander66]

I used the McFarland ring