Another Grendel that won't extract a spent case. with Pictures. Help!

[surfNshoot]

Well I've been trying to sort out this grendel for some time now and I have just hit a wall. I have a Satern 20" rifle gas system barrel. See pics below to see what is happening. I've had the help of very good gunsmith to get this sorted but I don't know what to do next. the issue has improved after the changes we have done but still only functioning about 60-70%. here is what I have done.

1. Tried the upper out and it short stroked very bad would not lock back the bolt at all. i took it to my smith and he took it down to check and make sure the gas system was working. He showed me that all was lined up correctly and messured the port at .093. He went back to his notes on a couple of alexander Arms barrells than he knew functioned correctly. one was a 19.5" with a .105 gas port and a 24" with a .106 gas port. He did not want to open the port up without some other testing first. I got a now buffer spring and started cutting coils to see if it got better. I cut 1 at a time up to 6 coils and no change.

2. Went back with the bad news. My smith opened the barrel to .098. I purchased another buffer spring and took it back out. At first it was doing the same thing so I started cutting coils again. After 3 coils cut I was able to get 3 shots off without failure but failed again. I cut more but could still only get a max of 3 shots off before failure.

3. Went back again. My smith was very hesitant to open it up more so he gave it another look over and all looks good. He contacted one of his guys that has a factory Alexander Arms barrel and messured it at .105 as well. so we opened it up to that. I put the factory buffer spring back in and took it out. first 5 shots when perfect but started doing it again but not Nearly as much. I don't want to open this port up anymore as I have seen that most people are working just fine in the .09X range. I'm stumped and don't know what else to try.

Here are the pics.

[bwaites]

That does not look like it is short stroking to me, it appears the bolt is going far enought to the rear to pick up the next cartridge, correct?

Two things come to mind here:

1) Proper ejector, meaning is it functioning as it should, proper depth?

or, more likely,

2) Extractor is catching the case rim and hanging on. Some extractors have such a sharp edge that they bite into the brass and hang on. A little emery cloth, or very gentle work with a dremel and fine sanding disk will fix this without a problem.

[surfNshoot]

Thanks. I will look into this. Yes It doesn't seam like it is short stroking anymore it just won't kick that shell out.

[StoneTower]

If it is a new upper...what are you using for lube? Break Free CLP is what you want to use. You need to run it wet. In the begining, make it wet and then add a little more. Your bolt and carrier look dry. I have fixed more than a few problems my friends were having in the field with a good shot of CLP.

[surfNshoot]

If it is a new upper...what are you using for lube? Break Free CLP is what you want to use. You need to run it wet. In the begining, make it wet and then add a little more. Your bolt and carrier look dry. I have fixed more than a few problems my friends were having in the field with a good shot of CLP.

I thought I might be called out on this. As you see it in this pic yes it was a little dry. I tore down the BCG and lubed everything with CLP. Lubed it very wet. Still have the same problem. Thank you for being so detailed though!!!!

[LRRPF52]

Does your upper have M4 feed ramps? Does your barrel extension have M4 feed ramps? Have you tried other mags?

As far as lubricants go, I only use Slip2000 now, which lasts longer than anything else I've seen, while remaining viscous...but yes, AR's need to run wet. Since you have a 20" barrel wit rifle-length gas, a larger gas port is necessary. Think about how much gas it will need in the winter.

Also, as Bill said, stove-pipes are an indicator of ejector or extractor problems. Test your spring tension on your ejector, and ditto on the extractor lip geometry. I had that issue with a factory DMPS LR308, and replaced the extractor.

[surfNshoot]

Does your upper have M4 feed ramps? Does your barrel extension have M4 feed ramps? Have you tried other mags?

As far as lubricants go, I only use Slip2000 now, which lasts longer than anything else I've seen, while remaining viscous...but yes, AR's need to run wet. Since you have a 20" barrel wit rifle-length gas, a larger gas port is necessary. Think about how much gas it will need in the winter.

Also, as Bill said, stove-pipes are an indicator of ejector or extractor problems. Test your spring tension on your ejector, and ditto on the extractor lip geometry. I had that issue with a factory DMPS LR308, and replaced the extractor.

Yes. I'm using a Larue upper with M4 ramps and the barel is M4 cut as well. Yes. I have tried 3 magazines now. 1 Cproduct mag and 2 Alexander arms mags.

I think it is all pointing to the extractor now. I will check it out when I get home. Gosh I can't wait to get this thing reliable.

[Mutt]

Cycle the action using the charging handle about 200 or so times manually, with very little oil. This will break in the parts a little and make them function smoother. My Grendel shortstroked and had feeding problems the first 50 rounds. So, I cycled it several hundred times to smooth out the new parts. It help alot. Then, I ran it wet (lots of oil) for the first couple hundred rounds. Now, it works 100 percent. You have to break in AR's. All the parts are painted or coated with layers of rough (in comparison to smooth bare steel) coatings that rub against each other and cause friction. The coatings need to be smoothed out by a little wear before they slide more freely. Most of my first malfunctions with my Grendel were caused by needing break in and magazine issues.

I was having a similar problem with my first C-products magazines. The feed lips stuck too far up into the rifle and rubbed against the BCG and the square hole where the magazine catch grabs onto the magazines weren't cut right. Even after tweaking the lips they still wouldn't run right. I sent them back to C-products and they sent me new ones. I still had to tweak the lips, but they ran much better. Oh, the Alexander Arms mags are also C-products mags but with an AA bottom plate.

Ya just can't take a new out of the box AR to the range and expect it to function 100 percent right off the bat. without break in. You have to be a little patient with it at first. It's usually around the 250 - 300 round count before it smooths out completely and starts to run smooth.

[LRRPF52]

Cycle the action using the charging handle about 200 or so times manually, with very little oil. This will break in the parts a little and make them function smoother. My Grendel shortstroked and had feeding problems the first 50 rounds. So, I cycled it several hundred times to smooth out the new parts. It help alot. Then, I ran it wet (lots of oil) for the first couple hundred rounds. Now, it works 100 percent. You have to break in AR's. All the parts are painted or coated with layers of rough (in comparison to smooth bare steel) coatings that rub against each other and cause friction. The coatings need to be smoothed out by a little wear before they slide more freely. Most of my first malfunctions with my Grendel were caused by needing break in and magazine issues.

I was having a similar problem with my first C-products magazines. The feed lips stuck too far up into the rifle and rubbed against the BCG and the square hole where the magazine catch grabs onto the magazines weren't cut right. Even after tweaking the lips they still wouldn't run right. I sent them back to C-products and they sent me new ones. I still had to tweak the lips, but they ran much better. Oh, the Alexander Arms mags are also C-products mags but with an AA bottom plate.

Ya just can't take a new out of the box AR to the range and expect it to function 100 percent right off the bat. without break in. You have to be a little patient with it at first. It's usually around the 250 - 300 round count before it smooths out completely and starts to run smooth.

I expect every AR I put together to function 100% from the start, and I'm usually successful achieving that unless introducing some new, unproven component. I polish the raceways on the bolt carrier to avoid the break-in with bolt carrier to upper friction, and using Slip2000. I also lube the recoil spring with Slip2000 to do the same thing with the anodizing inside the extension tube.

One thing that I would not want to do by cycling the action 200 times is wear out the recess for the charge handle latch on the upper. This is one design flaw of the charge handle that can cause the handle to come loose while you're shooting. A steel latch versus the aluminum upper will leave the steel latch the winner every time. You can forgo the 200 cycle break-in by polishing your BC raceways and using a thick, viscous lube. Some guys even polish the inside of the upper. A Milspec upper has a dry film lube baked into it after anodizing, which has a pretty rough finish as Mutt described, but serves as a good base for absorbing and retaining lubrication.

The last two AR builds I tested ran 100% in high-volume torture tests with M193 to the tune of 350 rounds per. If you have quality barrels with the corect gas port diameter, the correct bolt carrier weight, the correct recoil spring and buffer, decent mags, and the correct octane fuel, they will run.

I would advise against cycling steel on the dry film lube to smooth it out, since that is the porous base that will hold your lubrication better than worn and exposed aluminum.

[QuadCam]

check the ejector and ejector spring. they might be on the soft side. manually feed and extract several rounds. How far and where do they thrown from the receiver? I knew there was something wrong with mine when I manually tested it and it was making a weak little pile of bullets less that a foot away from the rifle. Also, look into the extractor and it's spring. you might have an issue there too.

[surfNshoot]

Yeah. I think its the extractor. It has some major sharp edges and it doesn't want to let go. I know it was short stroking at first but I hope I haven't over gassed it. Didn't seam to be. Who can point out how to tune this extractor? Can't believe I was doing this in my bedroom and not the garage.

[bwaites]

Depends on your tools. I use a very fine grit flexible disk on my Dremel and polish the edge. Go VERY gently, then recheck, repeat as necessary, but it's never taken me more than twice.

[Mutt]

I expect every AR I put together to function 100% from the start, and I'm usually successful achieving that unless introducing some new, unproven component. I polish the raceways on the bolt carrier to avoid the break-in with bolt carrier to upper friction, and using Slip2000. I also lube the recoil spring with Slip2000 to do the same thing with the anodizing inside the extension tube.

One thing that I would not want to do by cycling the action 200 times is wear out the recess for the charge handle latch on the upper. This is one design flaw of the charge handle that can cause the handle to come loose while you're shooting. A steel latch versus the aluminum upper will leave the steel latch the winner every time. You can forgo the 200 cycle break-in by polishing your BC raceways and using a thick, viscous lube. Some guys even polish the inside of the upper. A Milspec upper has a dry film lube baked into it after anodizing, which has a pretty rough finish as Mutt described, but serves as a good base for absorbing and retaining lubrication.

The last two AR builds I tested ran 100% in high-volume torture tests with M193 to the tune of 350 rounds per. If you have quality barrels with the corect gas port diameter, the correct bolt carrier weight, the correct recoil spring and buffer, decent mags, and the correct octane fuel, they will run.

I would advise against cycling steel on the dry film lube to smooth it out, since that is the porous base that will hold your lubrication better than worn and exposed aluminum.

Polishing the raceways on the BCG and other parts does basically the same thing. Either way, the parts need smoothed out either by firing, cycling or polishing to get the weapon to function 100 percent. Most manufacturers don't take the attention to detail like LRRPF52 does by polishing his build parts. The average AR builder usually only learns to do this after building his/her first build and relizing everything is a little too "tight".

LRRPF52 is right, when cycling you don't want the latch to catch each and every time you pull the charging handle. You want to hold the latch open and ride the charging handle in and out so not to wear out the recess for the charging handle catch. I should have been more specific in my post. Manually cycling your action a couple hundred times may seem like alot of work. But, in reality it only takes about ten minutes. Some surfaces such as feed ramps, I prefer to polish using a dremel with a small felt polishing bit and some rouge.

The extracters I have seen have all had those viciously sharp edges (points) on both sides. All of them needed to be filed down. A small jewelers file or small stone will do the trick. The very sharp points are totally unneccessary. All they do is cut the brass and will tear your brass up fairly well if you intend to reload. The only area that typically needed filing was the very tips or points and not the actual lip. Before filing, these points would cut slots in the base of every round I used, especially the Wolf (which is softer).

I do have to add ...... every time you show a pic of your parts, they are drier than hell. That can cause alot of problems in itself. Run that thing wet till you get it broke in. Don't get discouraged, it's smooth out. Just needs a little tweeking.

[surfNshoot]

I do have to add ...... every time you show a pic of your parts, they are drier than hell. That can cause alot of problems in itself. Run that thing wet till you get it broke in. Don't get discouraged, it's smooth out. Just needs a little tweeking.

Hahaha. I dried it off with a paper towel because I didn't want to get all oily. I have new hope now. I'll report back the resutls.

[Mutt]

LOL ..... well at least it's clean ..... LOL.