Thread: Short barrels and full powder burn?

There is some weirdities in this though - some barrels just don't follow the rules or write their own despite the laws of physics and ballistics.

I have one here that is giving me an issue - it's a bog standard 1-10 Rem .308, but it just doesn't follow the velocity rules. With reloads I can hit the full case and start compressing the powder - with from what I can see no pressure signs at all and the main issue I have is with factory loads it just doesn't hit the ballistics charts by a long way off. If it was a sticky barrel that required more push I could understand it, but... As another example subsonic loads that work fine in another .308 are well supersonic in this one - it requires an entire grain less powder to get to a reliable subsonic velocity. Must just be a very slippery barrel, which from what I have in my head is the opposite of what should happen as 1-12" twist being the norm this barrel at 1-10" should be slower not slicker. For a factory barrel it's a bit of a head scratcher, I've never run into this before. It's not lacking for accuracy, just horsepower to get to a decent distance without falling off a cliff.

As far as barrel length and powder burn - the .22LR is a good example of this. Max speed is usually in the 14-16" barrel range, some 24" or 26" barrels actually run slower velocities than the shorter ones.

Originally Posted by No.3

There is some weirdities in this though - some barrels just don't follow the rules or write their own despite the laws of physics and ballistics.

I have one here that is giving me an issue - it's a bog standard 1-10 Rem .308, but it just doesn't follow the velocity rules. With reloads I can hit the full case and start compressing the powder - with from what I can see no pressure signs at all and the main issue I have is with factory loads it just doesn't hit the ballistics charts by a long way off. If it was a sticky barrel that required more push I could understand it, but... As another example subsonic loads that work fine in another .308 are well supersonic in this one - it requires an entire grain less powder to get to a reliable subsonic velocity. Must just be a very slippery barrel, which from what I have in my head is the opposite of what should happen as 1-12" twist being the norm this barrel at 1-10" should be slower not slicker. For a factory barrel it's a bit of a head scratcher, I've never run into this before. It's not lacking for accuracy, just horsepower to get to a decent distance without falling off a cliff.

As far as barrel length and powder burn - the .22LR is a good example of this. Max speed is usually in the 14-16" barrel range, some 24" or 26" barrels actually run slower velocities than the shorter ones.

Long throat? Large chamber dimensions? 5r barrel?

Originally Posted by veitnamcam

Long throat? Large chamber dimensions? 5r barrel?

Rem factory chamber, so it's not unusual to get a factory round that feels 'tight' on closing. Not a 5R barrel, they are 1 in 11-1/4" twist in .308. Mine is a standard 1-10" twist off the .30-06 tooling but in .308 - so there may be something there as the usual Rem factory .308 offerings are 1-12". I got this new as a multi-use rifle subs and supers - does this well as happily stabilises everything I've been able to get my hands on for sub loads and am currently using 175gr Sub-X pills. It's just the supers that are odd.

Don't know about long throat, but it doesn't look visibly different to my other .308 Rem barrels and I'd assume the same chamber... I have another that has "only just come back from having the barrel swapped about 3 years ago" haha - need to get that up to the range and do a side by side comparison with it to try and work out what the - is going on with this one.