New AR 6.5 Grendel Problems

[gungate]

I took my recently built AR 6.5 Grendel to the range yesterday and it had problems. It would not fully seat rounds and the rounds it tried to seat got stuck in the bore. The first one that got stuck I had to separate the AR lower and upper and use a tool to pry the bolt back. I tried again and it got stuck again. This time I just used both hands and was able to force the charging handle back and free the bullet. Next one actually fired. I had one more stuck which was also able to be removed using the charging handle and force and after that I called it a day. The bullets that did not fire had a very faint firing pin indentation so I think they were not seated in the bore all the way.

I am using a batch of 300 reloads that I made a few months ago. I used 100 of these rounds in a competition (the first real shooting of this new build) and it ran flawlessly. The bullets referenced above are from this same batch. I did use Hornady 1 shot to lube the bullets prior to reloading. And, I haven't cleaned the gun since then. I also did not do any cleaning of the bullets after reloading and was wondering if the Hornady 1 Shot might have gummed up the gun.

Thoughts?

 

[DavidA]

It is definitely something in the bore. Similar issue on my AR. 15 Grendel build. I used a PRI 6.8 10 round modified cut out magazine so I could feed round max coal 2.346. To get them to feed properly I had to file the lower portion of the barrel back as tops of bullets would come up the well and hang up on the barrel extension. Took maybe .01” off .

When I reassembled rifle and checked function the cartridges got hung just as your did. Cleaned out the bore and it fed 100%. I had gotten some filings into the chamber.

Any hoot, whenever I resize brass and prep I always stainless pin tumble brass before I put in primers ready for loading. Clean some rounds and the chamber and see if it functions.

 

[gungate]

It is definitely something in the bore. Similar issue on my AR. 15 Grendel build. I used a PRI 6.8 10 round modified cut out magazine so I could feed round max coal 2.346. To get them to feed properly I had to file the lower portion of the barrel back as tops of bullets would come up the well and hang up on the barrel extension. Took maybe .01” off .

When I reassembled rifle and checked function the cartridges got hung just as your did. Cleaned out the bore and it fed 100%. I had gotten some filings into the chamber.

Any hoot, whenever I resize brass and prep I always stainless pin tumble brass before I put in primers ready for loading. Clean some rounds and the chamber and see if it functions.

Thanks! I've been holding off cleaning it because I want to do a little more investigating. I'm going to make 5 rounds with no powder or primer the same way I make my other rounds and see if I can re-create the issue. If I put a case only in the bore, it seems to work with no issues and no sticking at all. It is like the barrel itself is contacting the bullet but I don't want to test this theory with a live round.

 

[Squaregrouper]

Thanks! I've been holding off cleaning it because I want to do a little more investigating. I'm going to make 5 rounds with no powder or primer the same way I make my other rounds and see if I can re-create the issue. If I put a case only in the bore, it seems to work with no issues and no sticking at all. It is like the barrel itself is contacting the bullet but I don't want to test this theory with a live round.

I agree with DavidA.
Seat a few dummy bullets a little shorter than previous and see if the problem goes away.

 

[gungate]

So I have been working on this. I did not seat any dummy rounds because with some testing, my issue appears to be with the casings. I totally disassembled the bolt and thoroughly cleaned and lubed it. I also thoroughly cleaned the bore and seating areas. You can see the video below of what is happening. I also measured my cases they are well within spec. I tried several cases and all react this way. This is also from the group of 300 that I reloaded and shot 100 with 0 issues. I am at a loss what to try next other than to send the upper back to BCA and let them have a look.

 

[John from MD]

I took my recently built AR 6.5 Grendel to the range yesterday and it had problems. It would not fully seat rounds and the rounds it tried to seat got stuck in the bore. The first one that got stuck I had to separate the AR lower and upper and use a tool to pry the bolt back. I tried again and it got stuck again. This time I just used both hands and was able to force the charging handle back and free the bullet. Next one actually fired. I had one more stuck which was also able to be removed using the charging handle and force and after that I called it a day. The bullets that did not fire had a very faint firing pin indentation so I think they were not seated in the bore all the way.

I am using a batch of 300 reloads that I made a few months ago. I used 100 of these rounds in a competition (the first real shooting of this new build) and it ran flawlessly. The bullets referenced above are from this same batch. I did use Hornady 1 shot to lube the bullets prior to reloading. And, I haven't cleaned the gun since then. I also did not do any cleaning of the bullets after reloading and was wondering if the Hornady 1 Shot might have gummed up the gun.

Thoughts?

Did they fit in a cartridge length gauge?

 

[John from MD]

I just noticed you mentioned BCA. If it is a Bear Creek Armory barrel, that just might be your problem. I have inspected at least a half dozen barrels from them and not one was in spec.

 

[gungate]

Did they fit in a cartridge length gauge?

I checked with a caliper and case length was 1.50.

 

[larr]

I checked with a caliper and case length was 1.50.

Take a piece of brass and bump your shoulder back a little with your sizing die and retry .

 

[John from MD]

I checked with a caliper and case length was 1.50.

Caliper won't do the job in this instance. You need a SAAMI Cartridge Length Gauge. This is one I recommend if you are serious about making precision ammunition.

6.5 Grendel Ammunition Gauge

Choose between SLOTTED or NON-SLOTTED. AMMUNITION GAUGES are uniquely designed to check loaded ammunition, giving you the ability to check your factory ammunition or reloads against a spec chamber. The gauge is machined to the SAAMI minimum chamber spec for the 6.5 Grendel caliber. This…

sheridanengineering.com

 

[gungate]

Take a piece of brass and bump your shoulder back a little with your sizing die and retry .

Well poop.... I pulled a couple bullets and also the empty brass I have and ran the cases through the sizing die (only). Those cases now work perfectly. I seem to remember when I was running the batch one of the cases got stuck in the resizing die and I had to pull it out and hammer it in a vice to remove the stuck case. I bet I put it back in the press without setting it up again. The only way for me to know what bullets are going to work is to try each one and see which ones cycle properly. Tedious for 200 rounds! But I think I have this problem solved!

Caliper won't do the job in this instance. You need a SAAMI Cartridge Length Gauge. This is one I recommend if you are serious about making precision ammunition.

6.5 Grendel Ammunition Gauge

Choose between SLOTTED or NON-SLOTTED. AMMUNITION GAUGES are uniquely designed to check loaded ammunition, giving you the ability to check your factory ammunition or reloads against a spec chamber. The gauge is machined to the SAAMI minimum chamber spec for the 6.5 Grendel caliber. This…

sheridanengineering.com

How does this rate to the Lyman block below which I use?

 

[Squaregrouper]

Well poop.... I pulled a couple bullets and also the empty brass I have and ran the cases through the sizing die (only). Those cases now work perfectly. I seem to remember when I was running the batch one of the cases got stuck in the resizing die and I had to pull it out and hammer it in a vice to remove the stuck case. I bet I put it back in the press without setting it up again. The only way for me to know what bullets are going to work is to try each one and see which ones cycle properly. Tedious for 200 rounds! But I think I have this problem solved!



How does this rate to the Lyman block below which I use?

The Sheridan is a Mercedes; the Lyman is a Camry. They both work.
The Lyman block will be much quicker than chambering each round to test.

 

[gungate]

The Sheridan is a Mercedes; the Lyman is a Camry. They both work.
The Lyman block will be much quicker than chambering each round to test.

The Lyman block is crap. It shows all the rounds are perfect. I just ripped them in a review on Optics Planet. I ordered the Mercedes!

 

[Rocinante]

Does the barrel match the bolt? Mixing Type I barrel with Type II bolt and vice-versa makes things not play nice.

If it's a Grendel Type I (7.62x39 bolt), remove the o-ring in the extractor. The extra spring pressure binds against the case rim and will cause that exact issue in your video.
If it's a Grendel Type II, make sure the extractor is actually a Type II extractor and not a 7.62x39 or even a 5.56 (I have seen both).

 

[John from MD]

Well poop.... I pulled a couple bullets and also the empty brass I have and ran the cases through the sizing die (only). Those cases now work perfectly. I seem to remember when I was running the batch one of the cases got stuck in the resizing die and I had to pull it out and hammer it in a vice to remove the stuck case. I bet I put it back in the press without setting it up again. The only way for me to know what bullets are going to work is to try each one and see which ones cycle properly. Tedious for 200 rounds! But I think I have this problem solved!



How does this rate to the Lyman block below which I use?

I can't really say as I never used Lyman tools for precision work. I will say that the Sheridan gauge is made for minimum chambers and, the slotted version will allow you to see how your case neck and crimp sit in the chamber, how the bullet you choose sits in the lead and how well your sizing die reforms the case. Just because you buy a size die for a caliber doesn't mean that it is the most precise.

 

[Squaregrouper]

The Lyman block is crap. It shows all the rounds are perfect. I just ripped them in a review on Optics Planet. I ordered the Mercedes!

Odd. My Lyman works great for: 5.56, 6.5Grendel, .300AAC and .450BM.

 

[John from MD]

Does the barrel match the bolt? Mixing Type I barrel with Type II bolt and vice-versa makes things not play nice.

If it's a Grendel Type I (7.62x39 bolt), remove the o-ring in the extractor. The extra spring pressure binds against the case rim and will cause that exact issue in your video.
If it's a Grendel Type II, make sure the extractor is actually a Type II extractor and not a 7.62x39 or even a 5.56 (I have seen both).

Are there still Type 1's being sold?

 

[gungate]

Does the barrel match the bolt? Mixing Type I barrel with Type II bolt and vice-versa makes things not play nice.

If it's a Grendel Type I (7.62x39 bolt), remove the o-ring in the extractor. The extra spring pressure binds against the case rim and will cause that exact issue in your video.
If it's a Grendel Type II, make sure the extractor is actually a Type II extractor and not a 7.62x39 or even a 5.56 (I have seen both).

This came as a set from BCA. I assume they sent the right parts. How do I check?

 

[gungate]

Odd. My Lyman works great for: 5.56, 6.5Grendel, .300AAC and .450BM.

Are you sure? You ever had a bad round? I think it has too much slop since good rounds and bad rounds show identical.

 

[BigMac]

I took my recently built AR 6.5 Grendel to the range yesterday and it had problems. It would not fully seat rounds and the rounds it tried to seat got stuck in the bore. The first one that got stuck I had to separate the AR lower and upper and use a tool to pry the bolt back. I tried again and it got stuck again. This time I just used both hands and was able to force the charging handle back and free the bullet. Next one actually fired. I had one more stuck which was also able to be removed using the charging handle and force and after that I called it a day. The bullets that did not fire had a very faint firing pin indentation so I think they were not seated in the bore all the way.

I am using a batch of 300 reloads that I made a few months ago. I used 100 of these rounds in a competition (the first real shooting of this new build) and it ran flawlessly. The bullets referenced above are from this same batch. I did use Hornady 1 shot to lube the bullets prior to reloading. And, I haven't cleaned the gun since then. I also did not do any cleaning of the bullets after reloading and was wondering if the Hornady 1 Shot might have gummed up the gun.

Thoughts?

I had a 6.5 creedmoor get stuck in my chamber after not fully seating. It was also with BCA. Turned out there was a piece of something in the chamber, it left a mark on the neck. Have you looked at the stuck casings for any indications?