TOP Gun Theory
This podcast covers Chapter 3 of the new book: Modern Advancements in Long Range Shooting – Volume 3. In this Chapter/episode, we present a Theory of Precision for Guns – TOP Gun – in which we attempt to characterize the precision potential of any rifle based on a few accessible variables. Want to estimate what precision level you should expect from a hunting weight 300 Win Mag rifle vs. a bull barreled 223 varmint rifle? TOP Gun is a way to estimate the result.
I would be interested to hear your thoughts on muzzle brakes and the deviation to the norm given the underlying principal to top gun is recoil management ? This probably muddies the water as each one has different effectiveness.
I bet the muzzle brakes wouldn’t have a ton of influence on precision aside from their extra mass since they don’t affect the recoil during the time the bullet is in the barrel.
That’s a good question. Like Taylor mentioned, the brake couldn’t do anything about recoil while the bullet is traveling down the barrel and the gun is moving. However, the shooter-felt recoil is very different; not just what the shooter feels and reacts to, but also the front/rear rest getting moved more each shot, making things less consistent.
I wonder if correlating the precision to the system moment of inertia and/or recoil line deviation from CG might increase the correlation coefficient even more. It makes sense that a large rigid mass coaxial to the barrel would maximize resistance to torquing the POI off target while under recoil, while mass on an axis under the barrel would tend to force the POI upward while free recoiling. Likewise for the other directions.
Agreed! One example of a rifle that beats the TOP Gun trend predictions is the Barrett MRAD. What’s different about that – The chassis clamps to the barrel rather than the typical 6 O’clock recoil lug. IMO, the 6 O’clock recoil lug is terrible for setting up torques that create a bending moment and makes all kinds of severe asymmetries in recoil. I’d like to see a recoil lug/stock system where the load bearing is taken up at 3 and 9 O’clock rather than 6. Done correctly, this could mitigate the bending torque and possibly act more like the MRAD barrel clamp set up.
By how Much did the barret mrad beat TOP Gun trend predictions?
What magnification was used to shoot groups for each of the rifles? I wonder if shooting at lower magnification could account for some of the hunting rifles under performing for their energy/weight ratio.
Do you think there is a correlation between lock time of the firearm and the accuracy potential? More specifically when comparing AR platforms to bolt actions, since the lock times can be 5x slowing in ARs. This obviously wouldn’t effect the recoil movement before the projectile leaves the muzzle. But improper technique and lack of follow through might be more apparent on target?
A interesting point for top gun theory would be adding a lead sled as a data point. To see if a indirect addition of mass to the system can shrink group size.
Lastly a interesting case study would be say a 308 bolt action vs a 308 AR10 that weigh the same. 5-5 shot groups with different experience shooters. Just to see if one is “easier” to shoot due to lock time.
Regarding the idea of buying five different Remington rifles and comparing them to five custom rifles head over to Cal Zant’s Precision Rifle Blog and read his “6.5 Creedmoor Ammo Test Part 5: Live-Fire Group Sizes & Precision” article.
Scroll down to the section, ”Precision Differences Between Rifles,” where Cal compares the two rifles he used to generate his results. His chart comparing how the custom $5000 rifle and the $1300 out of the box mass produced rifle shot each sample of ammo directly addresses your question with very interesting results.