If a guy here has the exact same gun and barrel I have 18" SS lmt mws 308 and is getting 2475fps with 175smk's what ballpark fps would 155smk's be with the same or near same safe powder load?
308 fps question
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Re: 308 fps question
Something close to 300 fps faster.
In the more typical 24" tube, the 175 is generally shot at 2650 fps and the 155 scenar shot at 2950 fps.
Something close to 300 fps faster.
In the more typical 24" tube, the 175 is generally shot at 2650 fps and the 155 scenar shot at 2950 fps.
Re: 308 fps question
MitchAlsup is right. 175 FGMM clocks at 2,534 from my 20" AR, and 155 grain Nosler J4s using IMR 8208 XBR clocked 2,771 today.
MitchAlsup is right. 175 FGMM clocks at 2,534 from my 20" AR, and 155 grain Nosler J4s using IMR 8208 XBR clocked 2,771 today.
Re: 308 fps question
I've found that short barrels penalize you more with a light bullet than with a heavy. Using the same powder, you will have more of it to burn behind a light bullet and the light bullet will exit the barrel in less time. If 155's are 300fps faster with a 24" bbl per Mitch and 237fps faster with a 20" bbl per CTone then I'd guess you're going to pick up around 200fps with 155's vs. 175.
I've found that short barrels penalize you more with a light bullet than with a heavy. Using the same powder, you will have more of it to burn behind a light bullet and the light bullet will exit the barrel in less time. If 155's are 300fps faster with a 24" bbl per Mitch and 237fps faster with a 20" bbl per CTone then I'd guess you're going to pick up around 200fps with 155's vs. 175.
Re: 308 fps question
Why all the fascination with the 155's for the .308? Most of the time folks can't get them to shoot accurately (especially the secant ogive VLD types) unless they have a long barrel and a 1:13 twist. Stick with the 175's. Easy to find an accurate load.
Why all the fascination with the 155's for the .308? Most of the time folks can't get them to shoot accurately (especially the secant ogive VLD types) unless they have a long barrel and a 1:13 twist. Stick with the 175's. Easy to find an accurate load.
Re: 308 fps question
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Leaddog</div><div class="ubbcode-body">Why all the fascination with the 155's for the .308? Most of the time folks can't get them to shoot accurately (especially the secant ogive VLD types) unless they have a long barrel and a 1:13 twist. Stick with the 175's. Easy to find an accurate load. </div></div>
Who are these "folks" that your speaking of? The reason for the interest in the 155's in a .308 is because you can shoot them at 2900+ FPS and obtain near/close to .260 ballistics from your .308. Maybe this does not interest you for your particular applications, but it interests many people. Also, the 1:13tw statement is a little broad. I know "many" people shooting and competeing with the 155's shot out of a 1:11 to 1:11.25 tw barrel and doing excellent. One person happens to be a pretty well know instructor here on the Hide.
The argument between the 175smk and the 155 scenar has been hashed out many times over usually with the same general ideas that 155 performs superbly, but the 175smk rides the wind better, ecspecially out past 600yds.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Leaddog</div><div class="ubbcode-body">Why all the fascination with the 155's for the .308? Most of the time folks can't get them to shoot accurately (especially the secant ogive VLD types) unless they have a long barrel and a 1:13 twist. Stick with the 175's. Easy to find an accurate load. </div></div>
Who are these "folks" that your speaking of? The reason for the interest in the 155's in a .308 is because you can shoot them at 2900+ FPS and obtain near/close to .260 ballistics from your .308. Maybe this does not interest you for your particular applications, but it interests many people. Also, the 1:13tw statement is a little broad. I know "many" people shooting and competeing with the 155's shot out of a 1:11 to 1:11.25 tw barrel and doing excellent. One person happens to be a pretty well know instructor here on the Hide.
The argument between the 175smk and the 155 scenar has been hashed out many times over usually with the same general ideas that 155 performs superbly, but the 175smk rides the wind better, ecspecially out past 600yds.
