Range Report Recoil vs Muzzle Velocity
- Thread starter ACK
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I don’t know about velocity, but everyone I’ve watched that drove way to hard into the bipod (you know the guys push hard with their toes and need strips or spikes to keep the bipod from sliding), then tries barricades with light or no load, has large POI shifts. Either way, the POI shifts would worry me more as a shooter than a possible fps twitch true or not.
Working to keep the same type of load from position to position seems like a better use of time.
Working to keep the same type of load from position to position seems like a better use of time.
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i played/tested this very thing after hearing someone say that high ESs/SDs can be caused by different loads on the bipod...while my tests did not include the fancy electronics i did come to the conclusion that the load on the bipod has little if any effect on velocity or ESs/SDs...if someone has high ESs and or SDs they need to look more at how they are loading and the components they are using.
In addition to reloading practices I conjecture his result could be caused by variances in the crono or the barrel. I would suggest that rather than testing AAAAAAAAAABBBBBBBBBB he run a test ABABABABABABABABABAB
Hey folks, author of the article here. Thanks for sharing and taking the time to read my work!
I'm here to answer some of your questions.
That's interesting that they would see POI shifts. It makes me wonder if they are stressing the rifle stock and action, or if the barrels weren't properly free-floated. I shoot with my bipod preloaded in F-Class competitions, but it's designed for PRS. It was good enough for me to earn my NRA Highmaster classification at 600yd. If preloading the bipod like that created massive POI shifts, I don't think it would be possible to get good scores.
That's an interesting suggestion. For the rifle I used, that would have taken a really long time. In order to use the F-Class front rest, I had to unscrew the front rail that my bipod attaches to.
Why do you think variances in the chrono or barrel lead to only 2 of the 20 rounds to be outside the norm?
I'm here to answer some of your questions.
That's interesting that they would see POI shifts. It makes me wonder if they are stressing the rifle stock and action, or if the barrels weren't properly free-floated. I shoot with my bipod preloaded in F-Class competitions, but it's designed for PRS. It was good enough for me to earn my NRA Highmaster classification at 600yd. If preloading the bipod like that created massive POI shifts, I don't think it would be possible to get good scores.
That's an interesting suggestion. For the rifle I used, that would have taken a really long time. In order to use the F-Class front rest, I had to unscrew the front rail that my bipod attaches to.
Why do you think variances in the chrono or barrel lead to only 2 of the 20 rounds to be outside the norm?
You miss understood my post. A bipod pushed into really hard shoot one way, it could be one hole. Then when that same shooter and gun shoot off a rope or rickety obstacle and the gun can’t be loaded there is most often a POI change.
This is well known and very common.
I see what you mean now, thanks for clarifying.
I can only share my own anecdotal data here -- I haven't seen this issue on my rifle.
At my range, I have to zero at 100yd off of a slippery concrete bench without the 2x4 rig pictured in my article. I would expect a significant POI shift to mess up my dope at the 200/300/600 yard lines where I can preload my bipod, but it hasn't been a problem.
You mentioned that this is well known -- I'd love to read more about folks who have experienced this. Would you mind sharing some articles which discuss this phenomenon?
Hi,
So to even more complicate this debate
Can the results from the test be recreated when utilizing a top mounted bipod in which the rifle "hangs" under the support instead of balancing on top? Are those results the same whether loading or unloading or semi free hanging?
Also can the results be recreated by unloading the bipod with what you think is same pressure as loading the bipod? I ask this because with the Tac50s at the NSWC....they stopped teaching loading the bipod over a decade ago and went with unloading technique due to how the muzzle brake acts and the muzzle brake induced error. What was found was on average 1.5MOA of less elevation was needed when unloading vs loading (I will attempt to dig up the NDIA article on that).
Sincerely,
Theis
So to even more complicate this debate
Can the results from the test be recreated when utilizing a top mounted bipod in which the rifle "hangs" under the support instead of balancing on top? Are those results the same whether loading or unloading or semi free hanging?
Also can the results be recreated by unloading the bipod with what you think is same pressure as loading the bipod? I ask this because with the Tac50s at the NSWC....they stopped teaching loading the bipod over a decade ago and went with unloading technique due to how the muzzle brake acts and the muzzle brake induced error. What was found was on average 1.5MOA of less elevation was needed when unloading vs loading (I will attempt to dig up the NDIA article on that).
Sincerely,
Theis
The goal of course is always to have as little offset as possible. This is done by not having extreme differences in recoil control, be it because the shooter is managing all positions the same or the guns are super heavy with low recoiling rounds like a 6mm.
Again, my example of guys over-driving their bipod is the guys pushing with their toes or needing devices to keep the bipod from slipping forward; then suddenly finding a situation that they can not load. A lot of this comes from how the butt of the rifle is allowed to drive down in an unsupported position like sitting on a cattle gate with a standard type rifle. These guys almost always shoot higher in the latter scenario.
Your examples both use rear bags to help eliminate the rear dive.
Also remember that any gun that does not need much shooter input like the heavy, low recoilers are also less subjective to these issues and one of the main reasons you see the move to heavy 6mms, like the 6BRA in PRS type events.
All that said, I really don't think we need to link to any articles, hopefully you understand NPA because most of this is wrapped up in this alone with consistent recoil control.
Lowlight addressed this in in detail in the Online Training forum back in November..............................of course you'd have to sign up.
Thanks for the heads-up. Do you know if that material is available anywhere outside of that paid-subscription forum?
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