9.5 in 1 twist

[FW!]

will a 147g fmj shoot OK in a 9.5 in 1 twist or do I have to stick with 168g - 170g byllets?

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[High Plaines Doug r]

If you are talking about a 1 in 9.5 twist, a 147 gr bullet should shoot fine.

[FW!]

Thanks FW! I knew right after I posted that it should have said 1 in 9.5

[John Kepler]

Uhhh....some mention of the caliber is always nice if you want a meaningful answer!

Assuming it's a .30 cal.....who the hell makes a 1-9.5?

[MEHavey]

Mauser`98 (at least according to Hornady)

:-)

[John Kepler]

Mauser`98 (at least according to Hornady)

:-)

In a .30 cal.? The only Mauser 98-type .30 cals I'm aware of are the M1910 Mexican converted to .30-06 and some 1950's .308 conversions (Israeli). Or are we talking about an 8mm?

.30 cals generally have TR's between 1-10 and 1-12 (with some notable exceptions....mainly Palma competition barrels that are usually 1-13). I don't even know of any barrel-smith that cuts a 1-9.5 .30 cal., or why you'd want one (my 1-10 .300 Win barrels do just fine stabilizing 240 gr SMK's at 1000 yds!)

[FW!]

Savage in the short action .308 law enforcement model

[John Kepler]

I wonder what the hell they were thinking! A 1-9.5 in a .308 is over-reving the ball to no good purpose other than lowering the velocity, while increasing the bore-pressure and throat-wear! Don't make sense!

[Pete D.]

Just how much pressure increase/overreving do you expect a 1/2 inch change in twist rate is going to cause?? May be a non-issue.
Pete

[John Kepler]

How much? Let's put the same change in a different context.....how large an increase in bore pressure would you expect if you bumped the load by 5%? Think it'll be a "non-issue"? That's what the "half-inch" represents, and the effects will be similar!

In another context. Try to get a 155 gr. bullet in a .308 up to 2900 fps in a 1-10 barrel without blowing something up! It's fairly easy in a 1-13.

Third context change. In .223, an 80 gr SMK on top of 24.3 gr Vihtavuori N540 is a beautiful load in a 1-8 TR barrel, and will be giving significant over-pressure signs in a 1-7.8!

Barrel TR and load pressures are NEVER "non-issues"!