Need comments regarding load test results, group size, fps, etc. 308

Give up on the TMKs already. Sometimes barrels just don't like certain bullets. Try the 178 bthp (not the amax, very different designs; also better bc than the 175 smk at a lower price) or the 190 smk. Also, 2650 is just fine for velocity in a 175. If you want better performance, change bullet or caliber. Pick what you want: less wind with more drop, or less drop with more wind- the 308 cannot do both- it isn't designed to. The 243 is, and you pay for the performance increase. The 155 Scenar is also a high performing bullet in 308- it will not give up ground to the 175 smk/tmk downrange.
 
I use the Hornady 225gr BTHP. I use a G1 BC of .710 because my POI is higher than the factory stated BC.

To the lands my COAL is 3.075" so I back it off .020"
 
I've competed in FTR with your exact setup.

All my loads shot better near the lands. Anything from 155 to 225gr. To my surprise the 225gr stabilized.

You can get a 155 Scenar going pretty fast out of your 26" barrel.

If you don't load close to the lands, you won't be able to use as much powder and your rifling/freebore will increase very quickly.

With the .250 freebore you're describing, the bullets are smashing into the lands.
 
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Maybe it would be worth loading at the riflings length just to see? no jump?

1:12 twist

But like I said, I will double check the scope, and shoot a known load, before trying 5 rounds touching the lands.

Question, if 44.5 gave me 7025 (max) .010 off the lands, am I really going to get a pressure jump shooting them just at the lands, or the same load is fine?
 
In a boat tail bullet, the heel of the bullet is considered the point where the bearing surface ends.

Prior to a custom build, some gunsmiths suggest sending a dummy round to them with the heel of the bullet aligned with the neck/shoulder junction so they can throat the rifle accordingly.

Ideally, your rounds should look like this for maximum efficiency.

http://3.bp.########.com/-7GleDPPbzzs/T5QqSHJpICI/AAAAAAAADio/Qi8w5E-euso/s1600/IMG_1243.JPG
 
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The VLD bullets with a secant ogive like a jam in the lands or a very very short jump.

The SMK's tolerate jump much better, I usually start with a .020" jump.

With a long freebore like yours, the 185gr Berger Juggernaut may be a good choice.
 
C23 said:
In a boat tail bullet, the heel of the bullet is considered the point where the bearing surface ends.

Prior to a custom build, some gunsmiths suggest sending a dummy round to them with the heel of the bullet aligned with the neck/shoulder junction so they can throat the rifle accordingly.

Ideally, your rounds should look like this for maximum efficiency.

http://3.bp.########.com/-7GleDPPbzzs/T5QqSHJpICI/AAAAAAAADio/Qi8w5E-euso/s1600/IMG_1243.JPG
Click to expand...

And This!! This is how I seat all my bullets. I take a bullet, sit it on top of the case, measure the total length, then subtract .300 to get my loaded length. 2.950 for 210's, 2.900 for 185's, 2.875 for 175's and so on.
 
That is a dilemma. Fwiw, the loads with 42.1 to 42.3 aren't much larger than the 168 groups. That load is also what the US military uses. Might be worth sticking to it and trying it at longer ranges before getting too frustrated with it. It may be just fine as is. Just don't push the velocity too far. 2650 will keep you safe across the seasons.
 
I think that if everything is fine with the scope and base and chassis, I'll do a full ladder test with bullets .010 off the lands in .5 increments.
 
Give your .308 Win a try with the 175 Sierra MK's, 44 grains of Varget with your CCI BR2, Win match brass. There are 4 of us running that load of just a hair over 44 grains of Varget and we get 1/2 moa out of both 24 and 26" barrels and twists from 1 in 10 to 1 in 12. Let me know what you think. Change into clean underwear when you are done!!!
 
Rotac said:
Give your .308 Win a try with the 175 Sierra MK's, 44 grains of Varget with your CCI BR2, Win match brass. There are 4 of us running that load of just a hair over 44 grains of Varget and we get 1/2 moa out of both 24 and 26" barrels and twists from 1 in 10 to 1 in 12. Let me know what you think. Change into clean underwear when you are done!!!
Click to expand...

I have 8 pounds of 4064 and no varget.
 
just double checked all scope rings, base, xbolts, everything was torqued to spec, I removed them all and re-installed torqued to specs again.
Wasn't an issue with that, but I wanted to make sure.

Wont shoot before next friday. Will report then.
 
Well - Some rifles just don't like certain bullets. It can be due to barrel harmonics, bullet geometry, you name it. There exists the temptation to try to overcome these phenomenon by load optimization, however, in the end you could be just wearing out your barrel and wasting time and money. This is based upon very personal experience...
FWIW - Try a temporary pressure point under the barrel, using a thin cardboard shim. Guess what the result of this test would tell you?
 
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