25 GT 10 twist

[Jrjones]

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Very cool

 

[urbanrifleman]

@urbanrifleman

I'm think 3600 will be a safe top end.

 

[806guns]

I'm think 3600 will be a safe top end.

I know it will speed up some more once broke in

 

[806guns]

Trying H4895 next. May be able to yield a little more fps. How would you seat this bullet in this case?

 

[Gabe22BR]

Jam into lands-.020”

 

[806guns]

Jam into lands-.020”

Don't think I can touch them with the 130 freebore. Havent tried though either

 

[806guns]

Bullet is currently seating about 3/4 in the neck with a oal of 2.355"

 

[Woollybugger]

So if a 257 Weatherby shooting 70gr bullets can only achieve 3868fps w/ 80gr of powder

How’s a 34gr capacity case gonna get 4000 fps w/ 70gr bullets ??
Efficiency???

GT case holds 44gr of H2O

 

[806guns]

Fixing to load some more with h4895 soon...

 

[std7mag]

@806guns,

It's been a while, how is development going?

For some reason I got to thinking about this cartridge the other day.

 

[806guns]

@806guns,

It's been a while, how is development going?

For some reason I got to thinking about this cartridge the other day.

Sadly haven't been able to shoot it since. Actually just sold the rifle. H4895 was my next try. I will likely do this again real soon

 

[806guns]

New shouldered prefit 10 twist is on the way! Went with a 22" and will be using some GAP brass or some Alpha. H4895 will be my main powder.

 

[806guns]

So this barrel will have a .128 freebore and this was a PTG reamer. Drewsprecision.com did the work and uses Wilson blanks.

 

[806guns]

22" 25 GT 10 Twist this setup is heavy at 16lbs

 

[Woollybugger]

So if a 257 Weatherby shooting 70gr bullets can only achieve 3868fps w/ 80gr of powder

How’s a 34gr capacity case gonna get 4000 fps w/ 70gr bullets ??
Efficiency???

Brass life will be interesting

 

[806guns]

Brass life will be interesting

I have some GAP brass and will test this. I sold the Alpha brass with the last barrel. When I can buy 1x fired brass at .37 3-4 more firings is good enough for me

 

[806guns]

H2O Case capacity GAP fired 25 GT brass