Re: Considering trading in 700 for AR10... thoughts?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: linebaugh500</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Falar</div><div class="ubbcode-body">There will be a significant loss in velocity if you handload. Gas guns will show pressure signs before bolt guns because the case is extracted before all of the pressure has dissipated. I can only get 155gr Scenars to the 2750-2800fps range in my 21" AR10. Check out the .308 reloading thread and look at how many guys are running 2900-2950 with 24"-26" bolt guns. </div></div>
Hmmm, maybe a semi shows pressure signs sooner, but I don't think than means you should load hotter for a bolt gun.
Consider factory-loaded ammunition. That stuff is typically loaded right up to maximum safe (SAAMI) pressure. This is driven by free market - if Black Hills' 168gr Match load is substantially slower than Federal's, Black Hills would loose business. And as we all know, these companies intend for that ammunition to be used in both bolt guns and AR15s (they don't offer "uploaded" bolt gun ammunition or "downloaded" AR15 ammunition).
I've never fired an AR10 and bolt gun - with the same barrel length - over a chronograph with common ammunition. However, I wouldn't be surprised if the bolt gun had a slight velocity edge due to its lack of a gas port. In your example, I think the 3"-5" of extra barrel length on the bolt guns explains most of the velocity gain you list.
Again, I don't doubt that semi-autos might show pressure signs sooner than bolt guns. But this just means that you need to adjust the baseline for your assessment of the pressure signs you're seeing for each type of gun - not that you should load hotter for one type or another.
IMHO, the best thing to do is fire a few different factory loads in your rifle and use the spent cases as a guideline. If your handloads <span style="font-style: italic">in that gun</span> show pressure signs beyond what the factory loads did <span style="font-style: italic">in that gun</span>, you need to back off a little. </div></div>
46.5gr of Varget under 155gr Scenars in Winchester brass is about the most I've been able to load in my AR10. There are guys running 47.8gr with the same bullets and brass through bolt guns, in my book that is pretty big difference.