My Striped Grendel

[bj139]

I have been assembling a Grendel from a 16" BCA barrel and bought an AA Overwatch in the meantime.
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The Overwatch is precise enough with Wolf steel, Hornady SST and AMAX.
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The 16" BCA barrel finally showed acceptable precision with AMAX factory ammo only.
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Yesterday, I started resizing Grendel brass for the first time and noticed something strange.
Guess which brass was fired in the BCA barrel sidecharger and which in the Overwatch with brass deflector?
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Finally, some dummy rounds with 85G Sierra bullets which I loaded into 6.5X55 in the 1980's.
I haven't decided on a powder to try for the Grendel.
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Until my last time at the range with the BCA Grendel, I was firing rounds without a gas block and just mortaring out the rounds with the side charging handle. It was easy against a solid wood bench. What are the implications of the stripes? Should I contact BCA for a return or just keep this oddity? It operates fine in both manual mode and gas operated mode. Would a smoother chamber make it easier to manually eject a fired round? Does anyone here have any experience with this? I live in Pennsylvania which still does not allow deer hunting with semi-autos so it must be manually operated.

[NugginFutz]

bj139,

Nice looking pair of boom sticks, and thanks for posting up your progress with that BCA tube.

Re: the 85 grain Sierra HP Varmint's. I've found that H322 worked wonderfully, with superb accuracy in a gun that has proven quite finicky about most other loads. My best accuracy node was at 28.4 grains. I'm fairly sure that IMR8208XBR would work pretty well, also, but H322 was one of my magic .243 powders in that bullet weight range.

The spent brass from that BCA is troubling, though. Those rings are clearly abnormal, and can't be doing anything good for your brass life. Further, while working with an adjustable gas block on one of mine, I started with the gas completely shut off. At no point did I ever have difficulty extracting spent cases. This makes me think that the rings you have may be having the effect of "locking" the brass in place.

I remember reading one or two other reports about rough chambers from BCA. IIRC, one owner was in contact with BCA, and had reported that they recommended having the chamber refinished. Whether or not you send it back to BCA, I would definitely have that chamber touched up with a finish reamer before sending too many more rounds through it for imprinting.

ETA: Rather than shooting without a gas block, I suggest blocking the gas port by either using a tubeless GB rotated so as to block the port, or getting an adjustable and shutting off the gas. It just feels bad to imagine hot gasses exiting so small a hole under such great pressure.

[bj139]

NugginFutz,

Thanks for responding.

I will take your suggestion of H322 for the Grendel since the Lee load data I got with the dies lists it for 85g up to 123g bullets and it seems to be the most efficient powder per unit weight

I will contact BCA to see if they will replace the barrel. If the brass were to separate at the rings, another round shouldn't chamber but if it did I wouldn't want to be around. The rings appear to be ridges. I can feel no grove inside with a dental pick.

Initially, I envisioned a jet of gas burning a hole in my carbon fiber hand guard so I had the gas block turned around so the holes did not align. After I was planning to get the gas working, I just decided to "wing it" and shoot with no gas block. The hand guard shows no evidence of damage, maybe a slight powder burn.

I just tried to cycle the dummy rounds through the BCA and the bullet stuck in the lands. It was pulled from the case on ejection. I had to knock it free with a cleaning rod. The 85g bullets are fatter near the nose than the Wolf steel 100g bullet. I guess the SAAMI chamber is tight.

[VASCAR2]

I think I would contact Bear Creek Armory and send them the photo of your brass. I'd also let them know about your erratic accuracy. Your AA barrel seems consistent, BCA doesn't. At BCA price point it's not surprising the quality may vary from barrel to barrel.

[NugginFutz]

I will take your suggestion of H322 for the Grendel since the Lee load data I got with the dies lists it for 85g up to 123g bullets and it seems to be the most efficient powder per unit weight

You may wish to consider the purchase of the official Grendel Reloading Handbooks. (Check AA's website or LRRPF52's signature for a link to AR15Buildbox.com or something like that.) They are truly a fount of information about anything you can imagine about reading this round. The authors went the extra mile: Their collaborative effort included pressure testing, terminal ballistics testing, etc. The books contain information you will never get simply by googling recipes from unknowns like myself. Further, while I can offer the customary (but seldom regarded) warnings about starting low and working your way up, etc., the bottom line is my barrel likes what it likes, and yours has its own particular wants and needs.

I just tried to cycle the dummy rounds through the BCA and the bullet stuck in the lands. It was pulled from the case on ejection. I had to knock it free with a cleaning rod. The 85g bullets are fatter near the nose than the Wolf steel 100g bullet. I guess the SAAMI chamber is tight.

This particular bullet likes to be seated short; partly because of the large meplat and partly because of the length of the bullet. Mine are seated at 2.210", and shoot groups at or under 1/2 MOA. If you seated longer than 2.240" (Hodgdon's recommended seating depth for the 85 Sierra HP), I suspect you're going to stuff it into the compound throat or lands.

IIRC, seating that bullet any longer would leave less than a caliber's worth of bullet seated inside the neck. (This is something I try to avoid with all projectiles - especially those with boat-tails - because it doesn't leave enough bullet shank in contact with the case mouth.)

[LRRPF52]

Those rings are very odd. I've never seen that before. Looks like the result of a burr during reaming that spun around and gouged 2 rings up near the shoulder.

[bj139]

I didn't get a chance to contact BCA today. I went shooting the 6.5 Grendel Overwatch and a 300 Blackout upper instead.
I finally got a sub one MOA 5 shot group from the Overwatch while shooting factory Hornady AMAX.
There are 4 shots in 0.38 MOA with a flyer to the upper left for 0.7 MOA total.
The 30 cal holes are from the 300 Blackout.
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The Blackout was shooting all over the place and I almost wrecked the Overwatch group by overprinting.
After, I was cleaning the barrel on the 300 Blackout when the scope slid on the rail. I then loctited the base screws.
I have to remember to always loctitite base screws and perhaps ring screws as well.

[bj139]

I emailed Bear Creek Arsenal yesterday about returning the barrel. Still waiting for a reply.

I started reloading the Hornady once fired Grendel brass. Some was over 1.520" in length after resizing so I decided to trim to 1.512". I seated some bullets without powder and made sure they cycled fine through the rifle without the bullet sticking in the lands as they had previously. They cycled fine. The COL was 2.123" with Sierra 85g HP bullets. I bought some HP335 and weighed the powder charge thrown by the Lee dipper to be 25.0 grains. The powder dipper chart shows 24.8 grains from that dipper. They are primed with federal small rifle primers (#200) and ready to add powder and seat bullets. The next dipper size throws 29g of powder. I think the max load is around 32g but I just want some easy shooting ammo so I will try the 25g. I have 16 rounds ready to finish. I may get to the range today if the rain stops.

[bj139]

I just got back from the range and made it an all Grendel day.
First the 16" BCA barrel.

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I decided to play a tracking game with turret changes as indicated. The SWFA scopes sure do track well. 10X on BCA and 16X on Overwatch.
People said the 16X was too much power but I think 10X is too little power for the Grendel. 16X seems just right. I would like to try a 20X.

The BCA barrel produced 1.25 and 1.0 MOA three shot groups.
I will take it stripes and all.

Then the Overwatch upper. This thing is boring. It is obviously a much better barrel than the BCA.
It is no effort getting it to shoot well.

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16 shots total, all I reloaded. Time to fill them up again.

[bj139]

Still no reply from Bear Creek Arsenal about returning the barrel. I re-sent the email yesterday.
The last time I emailed them about an order they responded within 2 hours.

This will affect my decision to buy from them in the future.

Still, accuracy from the BCA barrel is now acceptable at a bit larger than 1 MOA with 85gr Sierras.
About what I would expect from a $100 barrel.

Time will tell how this affects brass life. The striped brass has been reloaded one time.

[VASCAR2]

I'm old school I'd call BCA and ask to speak to customer service or tech dept.

[bj139]

I shot the BCA 16" Grendel barrel today and saw my first sub MOA 5 shot group (0.905").
These were the same load I listed above with a dipper full of HP335.
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It doesn't like the factory SSTs as much (1.445").
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Keep or return?

[Mytie]

I've gotten rings like that on my brass from using a Lee chamfer tool. I can't tell in the picture. You've got me worried now. I just started my first 6.5 Grendel build. I ordered a ar-Stoner barrel from Midway. I've read that BCA makes the 24 inch Grendel barrel.

[dreadpirate]

I like the idea of putting backup sights at 45 degrees just in case the boar (or whatever) decides to charge you!

[bj139]

Many years ago I had a buck running by me when I had a Contender pistol with a 4X scope. One pointed shot was all I got.
With a 10X scope on my Grendel the same thing could happen so the quick tilt sights might be useful.

[bj139]

I've gotten rings like that on my brass from using a Lee chamfer tool. I can't tell in the picture. You've got me worried now. I just started my first 6.5 Grendel build. I ordered a ar-Stoner barrel from Midway. I've read that BCA makes the 24 inch Grendel barrel.

These rings showed up after firing new factory SSTs. They were not due to reloading.

[bj139]

I received a return mailing label from BCA and decided to return the barrel for a replacement. I hope the replacement shoots as well as the one I sent back. I only sent it back because I was hoping it may be easier ejecting rounds without stripes. If I hunt deer with the Grendel it must be manually operated in Pennsylvania, at least for now.

[bj139]

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Locktite Blue coverage on barrel extension.
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Brownells barrel installation rod after pounding out barrel with 22oz framing hammer using installation tool as removal tool. I didn't think I could hurt it significantly.
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Boreoscope inspection camera of chamber. I really didn't get a good view of the grooves in the chamber. This is really an inspection camera to view in walls for construction since the head is too large to fit in a chamber. Funny it is called borescope.

I will post updates after I receive an replacement barrel. BCA has really stepped up to the plate in resolving this problem as others here have mentioned about Alexander Arms and other venders. I will definitely order another dual charging upper and other parts from them. I am thinking 20" Grendel to go with my 16" and 24" Grendels. Four inches seems significantly different.

[Lastrites]

By the looks of your Brownells rod it sure seems that blue lock-tite was holding on for dear life.

[bj139]

I tried hitting the exterior of the barrel with a 2x3 but it would not budge. Maybe I should have tried the 2x3 on the Brownells rod but I thought I needed the hammer.
It took quite a few hits to get it moving and even more after it was halfway out to free it. I would say it was essentially one with the receiver.
I heated it with a hair dryer before trying anything else. I don't know if it helped or not. I scraped most of the locktight off with a knife before taking it to the UPS store.