250 FTX and Lil'gun powder

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250 FTX and Lil'gun powder

Postby Tbk » Sun Apr 29, 2018 5:00 pm

Been working up some loads for my 98 mauser/ Rhineland 16", 1:16 barrel using the above components. Using Hodgdon load data as a guide, starting loads are 35 gr and max load of 38.5 gr. The data is based on a 24" barrel and fps. Run from @2,000 to 2,250.

I worked up to 36.5 gr and thought I'd see what kind of velocity it was generating. Mind you, my bullet is seated out a ways, just off the lands a bit, the case mouths are as sized, not expanded and I'm using some elderly cci 400 primers. Figured it ought to be somewhat lower than the published stats. Imagine my surprise when the chrono showed a pretty consistent fps of 2,440 out of what should be a mid range load! Could that fast twist and seating depth have that great an impact?

No obvious pressure signs, but the recoil....oof!
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Re: 250 FTX and Lil'gun powder

Postby Bmt85 » Sun Apr 29, 2018 5:33 pm

If I had to guess, they are using a .451 blank and 6 groove Enfiled rifling. I don't know for sure what they are using, but it seems a few manufacturers are taking the cheap and fast route to make 450B barrels. Meaning they are most likely buying blanks meant for 45 ACP barrels, which are .451 bore not .4515, and heavy twist rates. If that is the case here, then yes, it will have a big impact on velocities! How that will effect a bolt gun, I personally don't know, I don't have a bolt gun in 450B. IIRC, the Ruger 16" bolt guns are getting about the same velocity with factory ammo as a 20" Bushmaster AR with a 1:24 twist. Ruger runs a 1:16 twist, and there are a lot of them out there.

With that said, some of Hodgdons numbers seem a bit low compared to other load data, and what reloaders are seeing. However, getting 2,400+ fps out of a 16" seems to be a bit warm. Check your case heads and length change, see what you come up with. If they turn out good, then you shouldn't have a problem.
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Re: 250 FTX and Lil'gun powder

Postby Hoot » Sun Apr 29, 2018 8:23 pm

Bmt85 wrote:...snip...However, getting 2,400+ fps out of a 16" seems to be a bit warm. Check your case heads and length change, see what you come up with. If they turn out good, then you shouldn't have a problem.


I also don't have need for a 450b bolt gun but let me echo the above speculation and advice. Measure your case head expansion and how far if any, the cases elongated. The brass for providing longer length is not magically fabricated. It comes from somewhere else losing brass and that's never a good thing. Since you say that you didn't notice any pressure signs, I'm assuming the primers were neither flattened or worse yet, cratered. Bolt guns are a relatively new frontier aside from a few early adopters, so a lot of load data offered here, from back in the days of most 450b platforms being 1:24, .4515, AR based, will not transfer tit for tat. You are wise starting low and working up. Since you have a chrony, please post all your results so that others can benefit, both in terms of velocity and groups. This caliber was getting pretty predictable before the bolt guns (and single shots) broke on the scene in earnest. We need two sets of experiences and yours are no exception.

Here's an excerpt from a past range report with an MS Excel format: If anybody wants a link to the blank template to use for their range reports, with Excel or the Open Office suite, I can host it for download. The velocity Average and SD calculations are built into the template. Needless to say, It's not copyrighted ( :lol: ) so feel free to improve upon it and host your version.

Image

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Re: 250 FTX and Lil'gun powder

Postby Tbk » Sun Apr 29, 2018 8:50 pm

Thanks for the replies. I will start keeping track on where this goes. Thus far, the groups are running a bit larger than I would like. Whether this is a matter of a lousy military trigger and cut down stock or just poor technique, or both? Maybe when I get the proper stock fitted and the Timney trigger installed I can shrink the groups down under a couple inches.

In the mean time, I am just trying to develop some promising loads to refine. Thanks for the advise!

Tom K.
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