[Jeff_850]

I took my Bushmaster XM15 M4 Carbine out to the range. I shot from a benchrest, I was shooting dead center at the 100y range. My friend suggested that I shoot using a block of wood to support the rifle on to see how accurate I could shoot it. This changed the point of impact several inches up. I decided to go back to shooting from a bench rest and the point of impact was the same. Was this because my barrel isnt free-floating???
I talked to a few people, some said yes, some said no, that shouldnt happen.
Any ideas?

 

[Jeffvn]

I'm a bit confused by your discription (it happens fairly often so don't feel bad), so I thought I would seek clarification. You switched from a bench rest to a hard block of wood and it changed the impact point up by several inches at 100 yards. Switching from resting your rifle on a "soft" benchrest" to a block of wood under the foreend of the stock did that?

 

[Jeff_850]

sorry for not making it clear
i was resting the hand grips on the wood
that must have pressed up on the barrel

 

[mele]

Hum, I'm still a bit unclear also.

When you say "benchrest" I'm assuming sand bags or something else you were resting the front of the rifle on? Or were you shooting it by supporting the forend with your hand?

Either way, I chaning rest types on the forend shouldn't have THAT much effect. Now, anything that changes the harmonics of the barrel can shift the point of impact, so its hard to say for sure. Now, when you went back to the old way (no block of wood) did the point of impact shift back to where it was before, or did it stay the same as it was while using the block of wood?

MEL

 

[Nate_Sniper]

It comes down to whether or not your rifle has a free float tube or standard handguard? if it is detachable, then its non freefloated. If its a round style, non-detachable, then its freefloated. Send me a pic of it and i can tell you by looking at it. And i dont think the accuracy would be effected that much... if all the shots were in perfect alignment. like a straight line... example*
*
*
*
*
then it was your fault . But if they were all in a tight group above the target, means the scope's elevation needs to be adjusted.

 

[Jeff_850]

its not free floating, this is probably the reason why the point of impact changed the way it did
the groups were tight and consistant, and when i stopped resting the hand grips on the wood, the point of impact changed back to where it was