Experienced long range marksman... I need clarification

[SpeedTactical]

Is there any true to something I was told while at the range?

Someone said that if you rest the weight of your rifle on the magazine while shooting prone, that your zero will be altered. I was wondering if this is true or if the person that told me that may have been mistaken. For 3 gun we often shoot prone out to long distances and everyone uses their mag as a monopod when shooting prone, so I don't see this being a big deal, but I was wondering if there was any truth to this statement.

[2nd Mass]

Makes no sense. If you're in proper form through your optic as when you sighted it, you should be good to go. Be cautious of who you listen to at the range.

[SpeedTactical]

That what I was think as well but not sure I might be missing something. I clarified with him and he didn't mean it would alter the zero as a result of the mag being a unsteady surface/platform to use as a monopod. He said that the bullets are pressed upward by the weight of the gun resting on the mag, and thus the zero or point of impact would differ, since the placement of the bullet inside the gun is affected by the mag being pressed upward. When I tried to rationalize his point, I couldn't seem to. Since the bullet in the chamber is not connected to the mag anymore, & the tolerance of the barrel around the casing of the bullet is so tight that I doubt the mag pressing upward due to the weight of the rifle resting on it would affect your zero. Plus the bolt carrier is dividing the mag from the bullet in the chamber which is another form of avoiding this from affecting the zero.

[ja308]

I honestly don't know as I've never done it . Is there a reason your not using a sling ?

I do know that air rifles have a different point of impact when rested as opposed to a steady hold without a rest .

Personally I would nor recommend using a mag to get a steady position. If it were a good idea the military would teach it .

[DannyInSoCal]

The stress on the mag make the round change "position" in the chamber?

He's an asshat.....

[SpeedTactical]

@ ja308.. Thanks for the input. Typically I wouldn't be using my mag as a monopod, but specifically in 3 gun, they don't allow a bipod or anything like that unless your in Open class. Often the course of fire calls for a 300-600 yard shot taken from a spot with nothing, just plain sand or grass. So we lay prone and the most steady thing available to steady the rifle is to use the mag in conjunction with holding the rifle still to hit those long shots. If I was just plinking I wouldn't shoot this way, but I was practicing as I would in 3 gun, & that's when the guy told me that.

[50BMGBOB]

I think this is like bedding a stock. Yes, I know AR's aren't bedded like bolt guns but different stress on the barrel/action depending on how it is held or braced could make a difference with any gun. Probably not enough to matter but it could. Best thing is to try it and see.

[ja308]

@ ja308.. Thanks for the input. Typically I wouldn't be using my mag as a monopod, but specifically in 3 gun, they don't allow a bipod or anything like that unless your in Open class. Often the course of fire calls for a 300-600 yard shot taken from a spot with nothing, just plain sand or grass. So we lay prone and the most steady thing available to steady the rifle is to use the mag in conjunction with holding the rifle still to hit those long shots. If I was just plinking I wouldn't shoot this way, but I was practicing as I would in 3 gun, & that's when the guy told me that.

If a sling is allowed, that's every bit as good as a bi pod. I would suggest a GI type and just websearch how to use the loop sling . Or attend an Appleseed clinic, they teach sling use just like the USMC
We regularly fired into a 16 " bull at 500 yards from prone with just a loop sling .
IIRC 16" at 500 is just a little ove 3 moa .

Good luck and good shooting Sir .

[mafbloggerdanny]

once the bolt drives the round into the chamber, it's completely disconnected from the magazine. you could pull the mag out completely at that point and it wouldn't effect the round that's already in the chamber, so no there's no way its going to effect the accuracy of the rifle. Depending on what you're resting that mag on and how stable it is, it might effect your aim, but that's your problem not the rifle.

[Anthracis]

No issue whatsoever if you use your mag as a rest. I do it and I know others do as well. This is how Travis Haley teaches it also. I've taken shots to 300m on my AR using this technique with no issues. Just my personal experience. YMMV.

[Snoopy47]

[Jimi Jah]

Use 10 round mags and shooters bag, never a problem in California.

[mr2ndamendment]

IF using the mag as a monopod has any effect on your zero with an AR15 it certainly won't be of any concern for a 3 gun match or about 99% of all shooting you'd ever do with it. There's two issues in debate: 1) Does resting the mag on the deck affect barrel harmonics or some other intrinsic aspect about the gun that would throw the point of impact off, and 2) Does this platform throw YOU off as the shooter? I heavily doubt it does anything to the point of impact but it certainly leaves room for there to be a chance it'll throw you off when you shoot. Either way, I don't think this matters whatsoever for almost all cases.

On a side note:
I've heard people argue it can affect reliability, and I've see this to be true first-hand but it has to be a dirty rifle with WAY old and beat-up magazines with tilting followers. With modern guns and magazines, I've never seen reliability be affected no matter what you do with the magazine in the prone.

[chomomo]

Magazines tend to wooble

In my marksmanship training USMC, we were taught never to rest the magazine on the floor when shooting in the prone position. The correct form and posture when shooting prone wouldn't allow for the magazine to rest on the floor. Plus I remember the PMI's stressing the point the the old aluminum 30 rounders tend wobble. Thus affecting your ability to correctly sight in due to shooters countering the wobble by muscling in the rifle in the prone.

[PyroFox79]

In my marksmanship training USMC, we were taught never to rest the magazine on the floor when shooting in the prone position. The correct form and posture when shooting prone wouldn't allow for the magazine to rest on the floor. Plus I remember the PMI's stressing the point the the old aluminum 30 rounders tend wobble. Thus affecting your ability to correctly sight in due to shooters countering the wobble by muscling in the rifle in the prone.

To add to this I was told that it could cause a malfunction with the USGI mags