Ideal rate of twist for 7mm-08

Factory twist rates of 9.125" and 9.250" seem in all cases to really like 140gr projectiles and lighter.

I have a Kreiger in 9" that does well with 150's, OKAY with heavier but not ideal.Yes, longer as SuperCub stated.

What weight of bullets do you want to push and for what application?

If you are going custom target and very long bullets you get into more than just twist rates.
 
I have been building 7-08s for a long time now. I find that the 1-9 twist rate is just about perfect for everything offered commercially and will stabilize all hand loading bullets offered up to 160 grains. I can't see a lot of purpose on loading anything heavier in the 7-08 but if you insist, then a 1-8 twist will do the job but may overspin the light 120 grain monolithics.

It's a great choice for a hunting rifle and when one is set up properly with a good scope and tuned trigger in a stable stock it will take anything on four legs in Canada as long as you do your part and find out what works best in the rifle for your purposes.
 
TrevorMack said:
As title states, looking for peoples recommendations on best rate if twist for a 7mm-08
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I would suggest a minimum of 1 in 9", and possibly 1 in 8" if you want to shoot long distance or targets. Have a look at the twist requirements of the various 7mm bullets at the link below:

Berger Quick Reference Chart

Another choice if you are having a barrel made is to go with a 284 Winchester which has about 10 grains more powder capacity. Bit more up to the job with heavier bullets.
 
Main purpose is hunting rifle. Will spend time at the range but not too serious into target shooting. max distances will be 400 yards and thats just the range.
 
The old 7mm standard was a 10 twist but the 9 twist will cover any hunting bullet you will be using in the 7mm 08.
 
I have my 7mm-08 20" long barrel LH Ruger rifle using as a donor Sako 7mm Mag barrel with 280mm (1-11") twist and it shoots better than 3/4" at 100m three shot groups with Hornady 139gr GMX bullets.
What's more to ask for?
 
As the OP stated, he wants a hunting rifle. Based on my experience hunting with the 7-08 I see no reason to exceed a 140gr bullet. And your majority of over the counter ammo is in that weight range of bullet.

You will use up more boiler room with longer and heavier bullets reducing your ability to gain velocity with them. The 10-11 twist will stabilize up to 140s very well and you will gain a modest velocity increase over faster twist rifles. The 120gr tsx bullets are excellent performers out of my earlier run savage 11.5 twist barrels. That twist rate was designed for the majority of factory ammo offerings.

So if you still want an option to run heavier bullets or target shoot in a 7-08 then my vote would be the 9 twist. My 2c.
 
elkhuntr said:
As the OP stated, he wants a hunting rifle. Based on my experience hunting with the 7-08 I see no reason to exceed a 140gr bullet. And your majority of over the counter ammo is in that weight range of bullet.

You will use up more boiler room with longer and heavier bullets reducing your ability to gain velocity with them. The 10-11 twist will stabilize up to 140s very well and you will gain a modest velocity increase over faster twist rifles. The 120gr tsx bullets are excellent performers out of my earlier run savage 11.5 twist barrels. That twist rate was designed for the majority of factory ammo offerings.

So if you still want an option to run heavier bullets or target shoot in a 7-08 then my vote would be the 9 twist. My 2c.
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140 grain is a good bullet size for a 6.5mm but it is on the small side for a 7mm. You give up the ballistic advantage of a 7mm if you go with bullet that is too light. The 7mm starts to come into its own with a 168 to 180 grain.

As for twist causing a reduction in velocity, that is just a myth. Actual tests in a 308 show that going from a 1:12 to a 1:8 only reduces velocity by about 5 fps.
 
My 7x57 Zastava Carbine has a 1:8.7" (1:220mm) twist rate and stabilizes 175gr Sierra GameKing SBT bullets just fine.

Very good accuracy with 140gr bullets also.

Interesting to note the 7mm-08 and 7mm mag have 1:12 and 1:10 twist rates, respectively, in Zastava rifles.

Z98_7x57_FS_a_zps8ychyopx.jpg
 
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9.3mauser said:
Sunray? Is that you??
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I have no idea who Sunray is. I've been here about 6 years and have always used the same sign-on. Perhaps it is one of the names used by bigedp51. He's been banned at most sites in North America and keeps using different names. He's now "pete1955" at Accurate Shooter.
 
Ron AKA said:
140 grain is a good bullet size for a 6.5mm but it is on the small side for a 7mm. You give up the ballistic advantage of a 7mm if you go with bullet that is too light. The 7mm starts to come into its own with a 168 to 180 grain.

As for twist causing a reduction in velocity, that is just a myth. Actual tests in a 308 show that going from a 1:12 to a 1:8 only reduces velocity by about 5 fps.
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The Berger bullet chart recommends 1-10 twist up to the 168gr. 7mm-08 does not perform better with 169 to 180 grain bullets. The velocity is too low at that point and it looses its magic for smacking big game. A 139gr Hornady SST has a BC of .486. Thats between a 168gr and 175gr 308 AMAX. Fairly decent ballistics.

The 7mm-08 does well with the 140-160 grain range. Thats what it does best. Its not optimal to fire 308 weight bullets from a 7mm.
 
coleman1495 said:
The Berger bullet chart recommends 1-10 twist up to the 168gr. 7mm-08 does not perform better with 169 to 180 grain bullets. The velocity is too low at that point and it looses its magic for smacking big game. A 139gr Hornady SST has a BC of .486. Thats between a 168gr and 175gr 308 AMAX. Fairly decent ballistics.
The 7mm-08 does well with the 140-160 grain range. Thats what it does best. Its not optimal to fire 308 weight bullets from a 7mm.
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Your comments highlight a common problem in evaluating which bullet is the best for the job. Typically a lighter and shorter bullet will have a lower BC, but because it is lighter you can launch it faster. The heavier bullets are longer and have a better BC but you can't get the same velocity. Which is best? Bryan Litz, the external ballistician at Berger wrestled with that problem and came up with the Form Factor to compare bullets of different weights and BC's on an equal basis. He defined the Form Factor as the Sectional Density divided by the G7 BC. If bullet weight (sectional density) in a caliber goes up, but the BC does not go up proportionally, then Form Factor goes up (poorer). If BC improves relative to the weight then Form Factor goes down (better).

Berger makes it easy to pick bullets from their Quick Reference Sheet by including G7 BC, Form Factor, and required twist rate. Just do down the list in your caliber and select the Form Factor you want, and check that your twist is good enough for the bullet. Hornady not so much. They give G1 BC which is not that great for longer distances, and with a few exceptions do not give you G7, or the Form Factor, or the required twist. Their latest hunting bullets seem to be the ELD-X versions which have very low drag and are designed for hunting expansion. If you drill down to the specific bullet page, they do actually give you the G7 BC, and sectional density, so you can calculate Form Factor. But, you are left in the dark on required twist.

Hornady offer a 150, 162, and 175 grain in the ELD-X 7mm bullet caliber. The Form Factors for these three bullets are very good at 0.920, 0.902, and 0.893. If I was shooting the 7mm for hunting, I certainly would consider the 175 as the first choice. Didn't do the calculation, but I'm sure that bullet would need a 1:8 twist. The only issue is overall length of the cartridge. If you have to jam the bullet way back in the case, then you are going to loose velocity, and it might not be a good idea.

The other thing to keep in mind when selecting twist for a custom barrel, which I presume this one is, is that there is no changing the twist down the road. If for example you thought you might want to step up the power from a 7mm-08 to a standard 284 Winchester, you could simply rechamber the barrel to a 284 Win.

And getting back to the OP's question, while I think you could get away with a 1:9 (but not slower), there really is no disadvantage to a 1:8, so why not go 1:8 and be done with it. You can handle any bullet on the market today.
 
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