Grouping

[mesabi]

How do you guys find the most accurate loads for your rifles? I see most people firing groups from sand bags or a rest. Has anyone tried finding the most accurate load for your rifle using one of the rests that strap the rifle down and control the recoil? Would that give you the best results for mechanical accuracy in your rifle?

Hyskore® Dangerous Game™ Machine Rest

That is one of the rests I am asking about.

 

[Mike / Tx]

I have come to the conclusion, and this is from my own testing and ideas of how things come together in an accuracy load, that the rifle has to recoil in order to allow all of the free vibrations or harmonics to flow through the rifle as the bullet exits the muzzle.

If you have the rifle firmly affixed in a non moving device your not going to have the same results when it is released to free recoil.

I have used the lead sled and found loads which normally shoot great to not shoot worth a hoot. Then loads which were tweaked to the sled would not groups when shot from bags and allowed to recoil.

This is just my own conclusions and not very scientific, but enough shooting was done to let me know I wasted my money on the sled.

Your results may vary but I will put my money on a good set of bags or a tripod type front rest with a rear bag like the BR shooters use. More often than not the loads are more accurate than I can hold them.

 

[Old Grump]

I use a Caldwell sandbag rest to zero my scope or test loads then shoot again with and without sling but without the Caldwell bag. Don't have one in the field so I figure its best to try the gun without it before I call things good for the day.

 

[mesabi]

Thank you for the input Mike. I do not have much experience so I was curious.

 

[briandg]

Mike is pretty much spot on. A rifle has had a long, drawn out explosion occur inside the chamber, and that whole thing is ringing like the liberty bell, from barrel to stock. those vibrations need to be free and unhampered, just like they would be without any rest. Just as if you were firing offhand. Adding stress or pressure against it in any way will mess with those vibrations, and you will get inconsistencies that may or may not show up in accuracy or point of aim, but will, nonetheless, be there.

When a dangerous game double rifle is made, the smiths choose a load, and repeatedly test fire with that load. They will shim and clamp the barrels until they fire to a single point of aim, and then, solder the barrels together. You can't change loads, add a recoil pad, or fool around in any significant way without changing the point of impact, as that thing will have been regulated and sighted in to be fired offhand, and the bullets are leaving the bore when the rifle is starting into full recoil.

 

[mesabi]

Would it matter if the rifle was strapped down on say a free float tube of an AR-15? The strap would not be touching the barrel directly, but I could see that the added pressure on where the free float tube connects to the receiver would cause a change.

 

[briandg]

This will sound like a cowardly answer, but anything can change the results. Shooting off of bags, shooting off hand, shooting with a right or left cant, almost any change in your environment can and will make a difference. Since you are already talking about accuracy testing that is going to be looking for 1/10" variations from group to group, you need to make your test protocol as close to real world conditions as possible.

Since in real life, most shots are taken either with no rest and/or restraint but what the human body provides or with field improvised rests, you would be best served by avoiding rigidity in your rests, and allowing that rifle to recoil fully against either yourself or a heavy pad while you do your group research.

That rest looked intriguing. I suspect that fairly routinely you could run the routine of finding an accurate round, though, and bypass numerous candidates because the clamping and so forth caused vibrations to throw it a little wider than it should. I also suspect that you might occasionally find a load that only works when the thing is in the rest.

part of the problem is that any firearm has already started into recoil before that bullet has left the barrel. The same goes for barrel vibration. That powder "explosion" causes vibrations that must be consistent, and minimal, or the bullets will be thrown everywhere.