6-250 Loads

[Fast14riot]

Working up some provisional data in GRT for a rifle I acquired with a barrel I was prepared to pull and toss, but after scoping it, it looked to be barely shot.

Chamber dims are unknown, but I did find old RCBS dies marked 6mm-250. Necked up some rem 22-250 brass, ran them through the sizer and they chamber nicely.

Looking into some powders I have sitting on the shelf, I measured case volume and everything I could to create a cartridge and chamber in GRT. I will be starting with the Hornady 108 eld-m for initial pressure and charge weight data.

XMR4350
I have almost a full keg of this sitting on the shelf, through my research I have cross referenced Shooters World 4350 and old Accurate loading data as this powder was made in Czech Republic.

GRT says 38.5gr is about max right at 60,000psi and 37.8gr for OBT load and 2910fps. I will load a ladder from 36gr to 38.5 for pressure testing and velocity.

Shooters World Match Rifle
Have a few pounds of this I haven't touched and decided to run it through GRT to see what it says. Max load is indicated as about 35.5gr, OBT is 34.7 for 2920fps. I will load a ladder from 33.0 to 35.5gr.

Rifle is a Rem 700 with a Sako extractor and in a 40xb rimfire stock. Jewel trigger. Heavy Palma barrel 25.75" long

Will update this post tomorrow with target and velocity data.

 

[Edd]

You might compare loads for a 6mm International.

 

[Twdmar]

Hodgdon has 6-250 data and there are several threads here about the 6-250. 6xc data may help provide a little context.
Nice looking rifle.

 

[moondog]

Nice looking old track bike

 

[Fast14riot]

6 international had a couple variations, I have some data for it as well as the Hogdgon 6-250 data. I have cross referenced them with the GRT loads and the powders I have available for this rifle. I feel confident in safely working up a load.

 

[Fast14riot]

Nice looking old track bike

I've got thousands of miles on that old Miyata Pista. Its been stolen once and sadly I haven't ridden it in a while. I should again.

 

[moondog]

Back in another lifetime, I was into bike racing. 2 customs, a Gangle, and a Pleiades both of which I still have, somewhere. My first was a Serotta.
Always wanted a track bike. Them's some long crank arms mister!

 

[Fast14riot]

Back in another lifetime, I was into bike racing. 2 customs, a Gangle, and a Pleiades both of which I still have, somewhere. My first was a Serotta.
Always wanted a track bike. Them's some long crank arms mister!

They're 170mm, but I do have a 33" inseam. Being a true pista frame it does have a high BB. Plus that's only a 46T up front, so they look longer in comparison.

 

[Fast14riot]

Tried shooting test ladders today, but it was 99° by 11am and no shade today. Got a few rounds off, but they were hot and hard bolt lift. Figured I should save them for when I can shoot in shade or more normal conditions. Had my ejector get stuck back, too. One of the few things I didn't pull apart to clean.

Oh well. Will hopefully get more thorough testing done soon, but now I have a few fired brass I can take better measurements from to improve my GRT load file.