Follower or clip mag feed for bench accuracy?

[barnabus]

Would there be an accuracy advantage of single feeding an AR10 from the bench vs. allowing the mag to feed the weapon during a long range scored bench match? If so,explain why.Thanks
Barnabus

[ICANHITHIMMAN]

The only reason guys single round load in AR pattern weapons system is due to limitations in COAL because of detachable box magazines. When you see guys single round loading their rifle its beacuse they are shooting heavy long bullets in the 80g plus range thay will not fit in the confines of the mag system. More accurate at longer range? In most cases yes due to higher BC worth it? I have no idea if its worth it I suppose if you want to win it is. But it also depends on what type of comp we are talking about to.

[Kevin Thomas]

You could just try it and see, just to verify in your own rifle, but I'd go with the single feed. The transition from magazine to feedramp to chamber is not a gentile one. There's another point to consider here as well; OAL. Not the OAL you set when you loaded the rounds, but the OAL they'll reset themselves to when you trip the bolt. You're dealing with a very large and expensive kinetic bullet puller there, especially with the added mass of an AR-10 platform. I've never seen an AR-15 that wouldn't pull the bullets to some degree during chambering. This can go from very slightly (but still measurably) with mil spec ammo using neck sealant and a crimp, to quite dramatically when using minimal neck tension in match loads. Bottom line, and I keep repeating this, Service Rifles (autos in general) are not bolt guns, and they need to be treated very differently.

You've got a significantly different situation here than you do with M1s and M14s (which should NEVER be fed directly into the chamber), where this sort of action risks a slam-fire. These guns MUST be fed through a magazine, simply to retard the bolt velocity a bit as the gun goes into battery.

From a bench, I'd probably feed directly into a chamber, and close the bolt gently as possible.

[B-RAD]

Don't waste your time with an AR-10 but an AR-15 - yes... it will help...

[barnabus]

Originally Posted by B-RAD

Don't waste your time with an AR-10 but an AR-15 - yes... it will help...

do what? How about something to support a statement like this?

[roop]

last winter i purchased a bushmaster .308 orc. In my reloading experimental phase i did some testing with crimps and neck tension. Now, i don't have numbers in front of me but i can tell you that no matter how much i crimped the necks, the bullets would move. dependng on bullet weight and profile, it could be in or out. bottom line here, if you want consistent velocities, you need consistent chamber pressure. if you are plinking at distances under say, 300m you probably won't notice a significant amount of vertical stringing, but for competition accuracy my recommendation would be to let the bolt down about halfway, then release it, or use that foward assist to seat the bolt. that way you can be sure of consistent performance.

[Boss Hoss]

In a magazine fed semi if the magazine is used to feed the rifle if you had concentricity in your loaded rounds you no longer will.