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Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Tue Apr 26, 2016 9:06 am
by commander faschisto
Pics should be very instructive! I was being a bit tongue-in-cheek about the 2700+fps...to paraphrase Mark Twain, "There is hot, and there in damn hot..." I think that shot falls into the latter category... :shock:

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Tue Apr 26, 2016 10:28 am
by Hoot
Texas Sheepdawg wrote:Guys. That 2700fps shot was nuts. And the pressure signs were a very clear message that I absolutely must back it down at least by 4.0 grains. Being a single shot and not needing the gas to cycle, I'm thinking 40.0-41.5 would be much safer. I'll post some pics of that case and you'll see what I mean.


Something to keep in mind. A recipe that produces an acceptable result in a 1:24 twist will run hotter in a 1:16. Say a 1:24 rig really liked 43gr of Lil Gun with 230gr FMJs. I would not be surprised to see that same bullet like 41gr in a 1:16, especially a long 1:16 barrel. I might even be tempted to drop down to a slightly slower powder than Lil Gun. Say W296/H110/300MP.

Hoot

EDIT: Actually 300MP while employing similar base compounds as 296/110, has a coating on it that slows it down a small amount. Not as far as 1680 though.

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Tue Apr 26, 2016 11:00 am
by Texas Sheepdawg
Yes indeed as was my suspicions when I bought this rifle. But that's what I want to prove. I want to show the tangible differences between a single shot and a semiauto and also the changes that twist makes. Now also, I'm needing some recipes for 1680 - 275 grain Barnes and 300 grain FTXs. I have another test to run.

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Tue Apr 26, 2016 12:18 pm
by Hoot
Texas Sheepdawg wrote:Yes indeed as was my suspicions when I bought this rifle. But that's what I want to prove. I want to show the tangible differences between a single shot and a semiauto and also the changes that twist makes. Now also, I'm needing some recipes for 1680 - 275 grain Barnes and 300 grain FTXs. I have another test to run.


I've loaded both of those bullets over 1680 with unacceptable results in my factory Bushy 1:24 back in 2012. So bad that I don't recall ever publishing the range report. 1680 over Rem 7 1/2 primers was way too slow for either of them. My gut feeling is that the difference in twist is not enough to buy back the velocity disparity compared to W296 which shot both of them more to expectation in terms of velocity. My original 1:24 Bushy barrel never met a brand of 300gr bullet that it liked in terms of accuracy. I doubt my 1:24 recipes will be of much use. With 1680, IIRC, I could not fit enough of it in my case to get to a pressure/velocity point where I could get in trouble.

That could well change with the 1:16 however. YMMV

Hoot

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Tue Apr 26, 2016 7:44 pm
by Hoot
Checked my range log and you can get up to 40.5gr of 1680 under the 300 FTX (SST ML) at 2.26 COL. I've loaded 300 XTP Mags which are shorter, up to 46gr 1680 at 2.22 COL (into the lands) and still had pressure and velocity to spare in my 1:24, so I doubt 40.5 will do you in, even with a 1:16.

John

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Wed Apr 27, 2016 4:47 am
by Al in Mi
I'll 2nd Hoots 46gr load and 300gr XTP mags, that's my pet go kill anything load in my 16".

Dawg, have you seated some dummy rounds to touch the lands yet?

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Wed Apr 27, 2016 7:26 am
by Texas Sheepdawg
Al, not yet. And the "16" referral is that this 20" barrel is a 1:16 twist. I don't want to load the same charges as we do for the 1:24 twist. With a faster twist, I'm already experiencing excessive pressure signs in my 230 Gr FMJ flat point penetrators.

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Thu Apr 28, 2016 1:06 am
by Texas Sheepdawg
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2731 just say NO!!!
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Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Thu Apr 28, 2016 2:08 am
by m113103
Did you measure any case head expansion? :P

Re: The New England Style Single Shot 450 Bushmaster.

PostPosted: Thu Apr 28, 2016 4:24 am
by Texas Sheepdawg
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image.jpeg (174.65 KiB) Viewed 14284 times

Hey Tim!!! Look. Not that I want to do it ever again but still!