Bullet weight/powder/recoil

[timmymic]

I am working on a 6 arc for my daughter who is going to be 7 for deer season. I know the 6 arc doesn't have much recoil but would like to minimize it as much as possible. Wondering how recoil works when changing bullet weights. When the bullet weight drops load data shows that you are running more powder... assuming the bullet isn't taking up as much room in the case. Which recoils more, a heavier bullet with lower speeds with less powder, or a lighter bullet going faster with more powder?
Would there be any noticable recoil difference between a 80/90 gr cx vs a 103 eldx?

 

[entoptics]

There's no "short answer" to this, though generally speaking, felt recoil will maybe be less with a lighter bullet.

Here's a calculator that will allow you to compare various loads, taking into account charge weight, for both recoil velocity and energy.

JBM - Calculations - Recoil

www.jbmballistics.com

 

[comfisherman]

ShootersCalculator.com | Recoil Calculator

An online calculator that calculates the recoil energy, impulse, and velocity of a firearm according to the firearm's weight, powder charge, bullet weight, and bullet muzzle velocity.

shooterscalculator.com

Play with load data, in that calculator and you can see the recoil speed and energy.

Firearms Recoil Calculator

Calculate the recoil for a rifle based on its weight and ammunition

bisonballistics.com

Another that shows the math

Nature of the equation means bullet weight and load charge in grains have impact, but noting like fps and rifle weight.

From doing lots of work getting little ones to shoot, they tolerate more energy in ft lbds if it's a slower impulse speed. Slower bigger push seems to be much more tolerated than a fast slap.


Edit to add, my personal preference is actually moderate weight projectile (so in a 6mm that would be 80-95 grains) over a starting load. Usually there is an accuracy node not far from the starting data. The animal won't know 100 fps, but stating vs max load can be non trivial in recoil perception.

As an aside note from introducing many new or young shooters, muzzle blast can cause flinch and negative shooting experience even more than excessive recoil.

 

[P7M13]

Depends on the rifle. Load a few of each and have her try them out. Is this an AR platform or a bolt?
Edit to add: how well the rifle fits her has a lot to do with perceived recoil.

 

[timmymic]

ShootersCalculator.com | Recoil Calculator

An online calculator that calculates the recoil energy, impulse, and velocity of a firearm according to the firearm's weight, powder charge, bullet weight, and bullet muzzle velocity.

shooterscalculator.com

Play with load data, in that calculator and you can see the recoil speed and energy.

Firearms Recoil Calculator

Calculate the recoil for a rifle based on its weight and ammunition

bisonballistics.com

Another that shows the math

Nature of the equation means bullet weight and load charge in grains have impact, but noting like fps and rifle weight.

From doing lots of work getting little ones to shoot, they tolerate more energy in ft lbds if it's a slower impulse speed. Slower bigger push seems to be much more tolerated than a fast slap.


Edit to add, my personal preference is actually moderate weight projectile (so in a 6mm that would be 80-95 grains) over a starting load. Usually there is an accuracy node not far from the starting data. The animal won't know 100 fps, but stating vs max load can be non trivial in recoil perception.

As an aside note from introducing many new or young shooters, muzzle blast can cause flinch and negative shooting experience even more than excessive recoil.

I agree with the muzzle blast comment. I am going to run my suppressor on there for her to try to avoid that. I'll take a look at the link you sent I appreciate you adding those.

Question I had while I was thinking about it but sounds like it may be a minimal difference with what your comment looked like. For an example CFE 223 and Varget are 2 options for powder. The CFE223 can get much faster speeds for the same PRESSURE. Was wondering if I used CFE 223 loaded down to get the speeds shown for varget which should come in significantly less pressure than the max load of varget. Would the CFE223 load have less recoil than the varget load since it has less pressure or would that be insignificant?

 

[QuietTexan]

Which recoils more, a heavier bullet with lower speeds with less powder, or a lighter bullet going faster with more powder?

Heavier bullet; the equation usually works out to 80-90% bullet weight, 10-20% charge mass.

Roughly speaking, (using an 8# 6mm rifle as an example) getting an 80 and 105 to the same velocity at the same charge weight (using different powders), recoil is 20% more for the heavier bullet. An 80 going 3400 is ~15% less than a 105 going 3000.

IMO put a 75gn HHT into it, light weight for a deer bullet, great performance, should shoot very flat also:

.243 Cal-075gr Hammer HHT - Hammer Bullets

AT THIS TIME TIPS ARE CONSUMER INSTALLED TIPPING BLOCK INCLUDED WITH EACH ORDER Designed for the factory twist .243/6mm caliber rifles, this 75gr Hammer HHT will easily load to 3600 fps in the 243 Winchester. The terminal performance and great speed of this pure copper bullet will be plenty for...

hammerbullets.com

I don't know if anyone could feel a difference between 80/90s and 100s in a 6mm. I can feel a difference in 30gn of bullet weight in a 30-06 but that's a much higher powder charge also, and I think I can only feel it because of a very poorly fitting stock that's a beating to shoot in general. Big misery factor with that rifle.

As an aside note from introducing many new or young shooters, muzzle blast can cause flinch and negative shooting experience even more than excessive recoil.

10/10

Edit to add: how well the rifle fits her has a lot to do with perceived recoil.

10/10

Regardless of what the paper math says, a suppressor and a stock that's more the right size would be much more impactful on what she FEELS than 30gn of bullet weight at 6 ARC velocities. I've seen kid shoot 22s better with double ears because they aren't used to the sound, and those have essentially no measurable recoil.

 

[MagnumManiac]

Snappier powder causes snappier recoil, so the numbers may be the same, but felt recoil is different. Try a ball powder to reduce felt recoil.

Cheers.

 

[Dmagna]

I think you are definitely thinking about this in a wrong way. The recoil on the 6 arc is so low as it is that you are nitpicking a few ft pounds of felt recoil. I assume that you are using ear protection, just use a brake and the best bullet you can get. I don't know how proficient your child is at shooting but when the adrenaline kicks in the recoil from that tiny cartridge ain't going to be a worry.

 

[wasskeet]

If it doesn't have to be carried, or not far - make the rifle weigh as much as is feasible. This will help about as much as anything.

 

[comfisherman]

He's got a can suppressor > break....

Weight is a good thing it factors in more than weight of the powder charge. Guessing its a Stable platform shot, no way even a hefty 7 year old is offhand shooting I'd surmise.

 

[FireFlyFishing]

I'd be more concerned on how to get my seven year old kid to hike, stay warm, and be quiet enough to be effective out in the woods in a hunting scenario. Even hunting from a blind or large tree stand would be challenging.

What rifle(s) has your daughter fired previously?

 

[Dmagna]

He's got a can suppressor > break....

Weight is a good thing it factors in more than weight of the powder charge. Guessing it's a Stable platform shot, no way even a hefty 7 year old is offhand shooting I'd surmise.

Missed that. I forget that cool people can buy those things. Here in new yorkistan we are not allowed suppressors.

 

[assasinator]

i just wanted to add and example.

my 17" 350 remington magnum pistol is my hunting gun.

two loads.......a 290 grain lead round nose......358009.
4198 = 2290 fps
4895 = 2100fps

roughly the same power, but the 4198 shot 2" high. the way it accelerated in the barrel changed the amount of recoil. it broke my bipod lug, and moved the scope. i pulled the bullets lol.

 

[BEEMAN]

I agree with QuietTexan. The 75 HHT was the bullet I was going to recommend. I have some and also the 55 HH to try in my 6 dasher.