Bench Vs Prone Shooting Variations
Years ago we addressed this, but never with something like muzzle velocity. The question and the demonstration has sort of been wrapped up into Recoil Management, but since we had the question, I wanted to demonstrate it.
The issue, a different muzzle velocity from the bench vs when shooting prone. The answer can be reduced to recoil management as I said, but let’s look at some visuals as well as some numbers.
We tested this 3 different ways, from the Prone, from the bench with our ass on the seat, bladed, and from the bench, with our elbows on the bench, body squared up. One of these positions showed a variation.
Point of impact wise, the bench position has a bit of a vertical as the point of impact was a fraction of inch high. (actually resulted in a dead center hit, but the zero was slightly low) This also resulted in a muzzle velocity variation too.
Muzzle Velocity Numbers
The following 5 shot averages were recorded:
Bench Back: 2696fps
Bench Forward: 2716fps
That is a 20fps muzzle velocity variation when the recoil is not properly managed. Huge in a lot of ways…
This change in impact can explain why you want to zero from a specific position especially if your recoil management is lacking. We preach recoil management because it will help avoid shifts in zero like we see here. My zero does not change, doesn’t matter the position I shoot from.
Recoil management not only tells us where the muzzle is when we zero the rifle, it effects how we zero the rifle. Letting the rifle control the movement usually requires more adjustment on the scope vs the shooter managing the recoil properly. Because recoil pushes the shooter back when sitting tall on a bench, we have the muzzle rising changing the point of impact. This movement also effects the muzzle velocity by moving the energy to the rear vs out the front. It’s essentially bleeding off muzzle velocity. In my case, 20fps.
So, you have to either measure and account for this, or at least understand the changes and how that can effect our dope.
This is shooter induced, vs mechanical, which is weird because it has a measurable effect. But we put so much into the shot, the Human Factor is huge and this demonstrates it.
It’s why I can argue that some of the science we talk about does not apply to everyone. It’s the nut behind the bolt.
Do your homework, especially if you shoot alternate positions because poor recoil management can have an effect on the shot not only at 100 yards, but especially at distance where these two errors stack up to one big error.
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