7 twist 22-250's

Re: 7 twist 22-250's

24" shilen select match 1-7 twist
80gr Amax
33.5gr Varget
CCI BR2 primers
2.5ish AOL
3200fps easy

P1010074.jpg
 
Re: 7 twist 22-250's

I've really been thinking about this cartridge with a 90gr pill lately myself. Should buck the wind decently if you get the velocity up around 3,000 ~ 3,100 fps.
 
Re: 7 twist 22-250's

Has anyone shot the 90gr Bergers over 3000 and got them to stabilize? That would be a great round either in a 22-250 or a 22-243. I spoke with a bullet smith/technician guy at Sierra and he told me that their 90gr matchkings would not stay together over 3000 out of a 7 twist. Anyone have some experience with either? I would be interested to know as well.
 
Re: 7 twist 22-250's

Someone here on the Hide had PM'ed me saying that he had good success for years with 80's and 90's in a 8 twist out of his 22-250.

I'd heard the same thing as you about bullets blowing up in 7 twist.

I wonder which bore and groove dimensions would work best for this application.I think shallower grooves would help but is it more or less grooves which would be more intrusive on the bullet?

As a side note.I never had problems with 115 6mm bullets destabilizing in some 8 twists I've owned even though 7-7.5 was recommended .?.?
 
Re: 7 twist 22-250's

3000fps from a 7-twist means over 5000rev/sec for the bullet. From anecdotal evidence, about 5000rps seems to about the limit for non-homogenous (cup/core) bullets. Anything over and you're in bullet blowup territory.

If someone made a bore-riding homogenous solid bronze alloy bullet~75-80grs, might have some possibilities.
 
Re: 7 twist 22-250's

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SingleShot85</div><div class="ubbcode-body">what the rev for the 80gr going 3200fps????
</div></div>

All depends on the twist rate. Bullets with thin jackets (varmint and match) are the most susceptible to over-spinning -jacket separation. IF it's an 8-twist then 4800rps. 7-twist then ~5500rps... Those AMAX's must be tough.
 
Re: 7 twist 22-250's

I have a 1-7 twist shillen, its pictured above. I shoot Amax bullets exclusively. 90% of the time I'm running 80's but I do use 75gr amax on occasion. All shoot tiny bug hole at every distance.

I never considered the bullet flying apart....glad it hasn't happened in my suppressor.
 
Re: 7 twist 22-250's

Here's one formula I found:
Quick Version: MV X 720/Twist Rate = RPM
I started looking because some 7mm 162 A-Maxs weren't making it to the target. At 3,150 fps through a 1-8 barrel the trace occasionally turns into puffs with no impact at the target. A riccochet sound can also sometimes be heard. That load never gave me any problems from a 1-9.5 twist barrel.

I had planned on a rebarreling a 22-250 with a 1-9 barrel shooting the 75gr Amax, but now I'm not so sure.
 
Re: 7 twist 22-250's

I personally as well as many others around my circle have had great great success running anything up to 80s in both fast twist 22-250s and 22-243s running anywhere from 3300-3450+. They are a blast to shoot no matter what. Someone on the hide owns a former stick of mine and can attest to the fun of watching that laser smack things while hardly ever coming out of the scope!

I really have not heard of many running 90s and that is the reason for my questions. The people that did try 90 matchkings said they either didn't shoot great or they didn't have the right something or other whether it was powder or chrony or barrel life left to have a significant answer on whether or not they worked. I have never heard of anyone trying the 90 VLDs out of either a 22-250 or a 22-243 variant of some kind.

Looking at Ballistic on my iphone if you can push a 90 with a BC of .594 @3000, anywhere close to 3250 or higher, and who knows what B.C. it would be @ 3200+ that puts them running 6.64 moa to 500yds and 20.33moa to 1000yds with 5.14moa of wind @ 10mph. It is still running 1837fps with 674ft/lbs of energy.

Sign me up, if they will stabilize.
 
Re: 7 twist 22-250's

f.w.i.w...

I've got a .22-243 in the works and going with a 1:8" (Krieger) for messing with the various TSX & AMAX offerings in .224 caliber...

Schweet stick, SS85!