Muzzel Velocity of Loads: AR vs Bolt

[DEC]

Since I don't have a chronograph, I would like to ask this of someone on the forum who has made this comparison: If I were to compare two exact loads (for example .223), and shot these same loads through an AR-15 and a .223 chambered bolt rifle, how would the muzzle velocity compare in each of these rifles?

Thanks

Dan

 

[RonAKA]

Here is the loading data for each. Just compare them for velocity.

http://accurateshooter.net/Downloads/sierra223rembolt.pdf

http://accurateshooter.net/Downloads/sierra223ar.pdf

 

[DEC]

OK... Thanks alot!

 

[Laurie]

Dan,

if you mean by your question how would the MVs of say factory ammunition, stack up against each other in the two rifle types, all other things being equal, the answer is "no difference". A tiny amount of the energy produced is diverted to operating the AR bolt, but if everything else were absolutely identical, you'd hardly see any difference on the chronograph.

Bolt-action rifles usually have longer barrels than ARs and can be loaded up to rather higher pressures depending on action make and model, and that's where they get their higher MVs.

Having said that, as a Brit who isn't allowed by his government to have a gas-gun (but owns a manually operated straight-pull AR15 and AR10), I'm more than a little impressed by Hi-Power Service Rifle ARs getting the 80gn SMK to 2,800 fps or thereabouts from a mere 20" length barrel - albeit 100 fps more than Sierra says is safely possible.

Laurie,
York, England

 

[Rock Knocker]

I like this question and have been wondering about it also. I will end up with a chrono soon enough though. Those Sierra tables are a good referance, the one problem is that they arent being shot out of the same length barrel(bolt-24", AR-20")

 

[seniorshooter]

Laurie, Could you please advise me of a starting load for my Rock River Arms AR in .308 with a 20" bull barrel (stainless)? I would like to use a 155 gr. bullet. Thanks, Seniorshooter