Bear creek Arsenal did away with their MOA guarantee

That 22-250 sure is tempting, as is the 17hmr. I just don't know that I need more mouths to feed with ammo and components hard to find and expensive. At that price point, there is no way accuracy can be assured to any reasonable degree, it's got to be a crap shoot. They didn't magically discover a way to drill, ream, and rifle a piece of steel that costs next to nothing but is just as good as a barrel that costs as much as their uppers do.
 
After doing more research on the magnum rimfire uppers as well as 17m2, it appears the straight blowback semi-autos suffer from spli/ruptured cases. Im going to pass, which sucks as I really wanted one.
 
Originally Posted By: Moose57I have an upper in 22 mag. I haven't shot it a lot yet but so far no split cases. It was made by BCA.

That's good to hear. And I wasn't knocking BCA nor is it a design flaw on their fault.
Apparently it's a well documented problem with straight blow back magnum rimfire rifles. Much less of a problem with a delayed blowback design.

This is not first hand knowledge on my part. Just what I've been told when I asked about the BCA 22WMR and 17HMR UPPERS.

https://www.ar15.com/forums/ar-15/BCA-17hmr-and-22-wmr-uppers/15-776273/
 
the risk with rimfire blowback designs isnt in the straight wall cases - its in the bottleneck cases like the hm2 and hmr. its also not the split necks that cause a danger to the shooter\.

what happens is carbon builds up at the shoulder in the chamber as the round is extracted, and over time, without proper cleaning, enough can build up so you have an out of battery situation where the firing pin still is operational. *kaboom* you blow the mag out of the magwell, and throw brass frags everywhere as the case ruptures in the unsupported portion sticking out of the chamber from the carbon buildup.

this is why the delayed blowback actions were developed, allowing the pressure to dissipate and lessen then chance of carbon getting deposited on the neck as most of the schmoo (yes thats a technical industry term heheh!) to go out the end of the tube, instead of gunking up the chamber.

the cracked neck issue crops up in the caliber every few years - but usually its been linked to batches of bad brass (too hard/not properly annealed type of thing). however the cracked necks are not a safety isssue to the shooter, unlike the OOB (out of battery) kaboom is.


not knowing if the bca 17hmr is a delayed blowback - they do not advertise it as such - is one of the few things that have stopped me from getting one. I'd love a 17hmr ar. but i'm not gonna risk a kaboom to have one. yes i know franklin makes (or used to make) a delayed blowback hmr... but last i looked, the upper prices were comparable to a high end barreled centerfire upper with a premium coated BCG in play.
 
The Alexander Arms 17hmr is a simple blowback and a buddy has thousands of rounds thru it without issues. They send a chamber brush to clean it every 100 rounds.

Not comparing the AA to the BCA, but I'm sure that's what they copied.
 
Tracking info says I will have a 20”BCA 308 upper tomorrow. I have 150 gr FMJ, 150 gr SST and 175 RDF loaded up ready to break it in. Hoping it’s a shooter.
 
Originally Posted By: 204 ARThe Alexander Arms 17hmr is a simple blowback and a buddy has thousands of rounds thru it without issues. They send a chamber brush to clean it every 100 rounds.

Not comparing the AA to the BCA, but I'm sure that's what they copied.

wow. good ole bill playing CYA. "sorry we sent you the tools, if it blew up, its your fault"

and yes i get it, but expecting someone to deep clean their rimfire every 100 rounds... well yea. there's a reason almost *everyone* else 86'ed their semi auto HMR's.

the problem i'd have with that.... both my 17 hmr's like to be shot dirty - its relatively common for the caliber from what ive seen on the forums over the years. they group for crap until they've got 30 or so rounds down the tube. then the groups tighten up to "normal". i only clean them (other than a quick pull or two with a boresnake with a little oil to prevent corrosion) every 500+ rounds... basically when it gets too fouled and the groups open up, which for me ends up around 700-900 rounds on average.

if i had to clean mine every 100 rounds, that would give me at best 70 rounds of actual shooting between deep cleans. which is ridiculous - having to waste that much ammo to maintain safety and accuracy... bye felicia, time for a new boomstick.
 
Originally Posted By: Plant.OneOriginally Posted By: 204 ARThe Alexander Arms 17hmr is a simple blowback and a buddy has thousands of rounds thru it without issues. They send a chamber brush to clean it every 100 rounds.

Not comparing the AA to the BCA, but I'm sure that's what they copied.

wow. good ole bill playing CYA. "sorry we sent you the tools, if it blew up, its your fault"

and yes i get it, but expecting someone to deep clean their rimfire every 100 rounds... well yea. there's a reason almost *everyone* else 86'ed their semi auto HMR's.

the problem i'd have with that.... both my 17 hmr's like to be shot dirty - its relatively common for the caliber from what ive seen on the forums over the years. they group for crap until they've got 30 or so rounds down the tube. then the groups tighten up to "normal". i only clean them (other than a quick pull or two with a boresnake with a little oil to prevent corrosion) every 500+ rounds... basically when it gets too fouled and the groups open up, which for me ends up around 700-900 rounds on average.

if i had to clean mine every 100 rounds, that would give me at best 70 rounds of actual shooting between deep cleans. which is ridiculous - having to waste that much ammo to maintain safety and accuracy... bye felicia, time for a new boomstick.

I wouldn't call running a brush in and out of the chamber a couple times a "deep clean". And not doing it just resulted in a couple malfunctions, nothing catastrophic. And to be honest, I've only ever been around one of these, and I've wanted one ever since but just don't shoot the rimfire enough to justify the cost. But if I could, I would not be scared of a kaboom at all, the set-up seems to work.

Now, again, that doesn't mean the bca will work as well, but I'm betting they copied the AA one pretty close.
 
It sounds like BCA can be hit and miss but I'm happy with the one I got. Seems well made, bolt locks up like it's polished. Cycled 150 to 175 grain bullets and locked back perfectly. I was able to get MOA out of the 3 different loads I shot. It says factory ammo only but my reloads worked. I was surprised how mild the recoil is in a 308 gas gun compared to a bolt action.
 
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