10mm hardcast - Buffalo Bore vs Underwood

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My old G20 was “loaned” out to a “friend“ fortunate enough to spend more time in bear country than me. It doesn’t appear likely to return anytime soon, so I am breaking in a new one. Did some parts swapping and the KKM barrel just arrived. Plan is to run 200-300 “cheap” rounds through her to break it in and then function test with some full octane hardcast rounds.

I had been a Buffalo Bore guy originally. A quick check shows Buffalo Bore and Underwood 220gr are readily available for the first time in a while. Post pandemic pricing being what it is, BB is $2.15 per round and Underwood is $1.30.

Assuming they both work in my boomer, any reason to preference BB over Underwood?
 
I’ve never shot any BB. My 29 and 20 have been on a steady underwood diet since I got them many years ago.
 
I had to send my KKM barrel back to get the transition area between the feed ramp and the beginning of the barrel smoothed out because it was jamming consistently even with round nose cci blazer, much less the square nose hard cast stuff.

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I would stick with the stock barrel even for the hardcast because the feed reliability is so much better than the tight tolerances in custom barrels.

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My KKM barrel has worked flawlessly. I have shot a lot of both types of ammo that you listed and I can’t tell a difference.
 
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I shoot Underwood, haven't had any issues, I carry them in mine. Can't really say they are better or worse than Buffalo Bore. No reliability issues regarding cycling, feeding etc. I've run them in a 6" Alpha barrel and and the factory.
 
I never shot the BB but the underwoods shoot really well out of my G20.
 
I've only shot .45 Super BB through my Glock 30SF with KKM barrel.
255gr. flat nose hard cast, no complaints.
Havent tried the Underwood.
 
I’ve shot bb through my lone wolf barrel with zero hiccups, but with the lead restriction while hunting in my neck of the woods I started loading Lehigh defense 190gn copper and am very pleased. My buddy threw one through the chrono the other day when we were testing some rifles and got 1200fps. With some hillbilly ballistics testing awhile back (stacks of cut off cedar fence boards packed tight in a beer box) we found that the hard cast and the Lehigh I loaded penetrated exactly the same number of boards. BB sells these bullets loaded and are also worth a look.
 
Thanks for the input, folks. I think I am going to function test a box or two of each and see what works. Assuming both do, I am tilting toward underwood based on price.
 
I would stick with the stock barrel even for the hardcast because the feed reliability is so much better than the tight tolerances in custom barrels.

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Stock barrel will tumble 220’s.
 
I’ve been shooting Underwood 220’s for years without issue, I have a Lone Wolf barrel.
 
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