375 Cheytac bullet tension

[actionexpress]

I am going to be reloading a magazine fed 375 Cheytac and was wanting to know how much bullet tension should I be looking for.

 

[Mike TackleBerry]

How heavy is the rifle and what bullet and velocity are you shooting it at?

 

[big5ifty]

You received responses on your other thread.

 

[actionexpress]

How heavy is the rifle and what bullet and velocity are you shooting it at?

sorry for the delay in responding
rifle will weigh 30 lbs.
cutting edge 377 gr MTAC-MAX
2900 fps

 

[Mike TackleBerry]

sorry for the delay in responding
rifle will weigh 30 lbs.
cutting edge 377 gr MTAC-MAX
2900 fps

Thats alot of recoil for a mag feed rifle, 20lbs more recoil energy than my 375, Id go .004 NT minimum. Problem with big boys like 375 and up is they recoil so hard that the rounds in the mag slap the front of the magazine and either push the bullets into the case more or they deformed the meplat of the bullet.

 

[Varminterror]

For what it's worth, a 377grn at 2900 over 138grn powder in a 30lb rifle has lower recoil velocity than a 10lb 30-06 pushing a 150grn bullet at 2950 over 60grns of powder...

Also for what it's worth: My 375 is a single shot, but I use 1.5thou neck tension, and I can't push the bullets deeper into the cases by hand. I use 3thou on my PRS rifle, 6 dasher and 6 creed, and I CAN push the bullets deeper into the cases if I really lean on the bench.

 

[Mike TackleBerry]

For what it's worth, a 377grn at 2900 over 138grn powder in a 30lb rifle has lower recoil velocity than a 10lb 30-06 pushing a 150grn bullet at 2950 over 60grns of powder...

Also for what it's worth: My 375 is a single shot, but I use 1.5thou neck tension, and I can't push the bullets deeper into the cases by hand. I use 3thou on my PRS rifle, 6 dasher and 6 creed, and I CAN push the bullets deeper into the cases if I really lean on the bench.

Using your inputs, the 375 has 33.62 ft lbs of recoil energy and the 30-06 has 17.48 ft-lbs. So essentially double the recoil. Post some pics of your Cheytac, Like to see it.

 

[Varminterror]

Using your inputs, the 375 has 33.62 ft lbs of recoil energy and the 30-06 has 17.48 ft-lbs. So essentially double the recoil. Post some pics of your Cheytac, Like to see it.

The recoil energy really only matters to the shooter receiving it - the recoil velocity describes how much inertia the bullets and ammo will feel as the rifle tries to move around them.

 

[Mike TackleBerry]

The recoil energy really only matters to the shooter receiving it - the recoil velocity describes how much inertia the bullets and ammo will feel as the rifle tries to move around them.

View attachment 1743423

Nice setup, Just noticed you said velocity and not energy my bad.

 

[Varminterror]

Nice setup, Just noticed you said velocity and not energy my bad.

Correct - the velocity (and really the acceleration) is the critical aspect for pulling bullets in recoil or running rounds into the front of the mag.

A freight train rolling backwards at 1/2 mile per hour will knock over a building, but the impact won’t hurt if it runs into you (until it runs OVER you). Alternatively, a much lighter, much lower energy baseball at 60mph can’t topple the building, but it’ll break our face if we take one to the teeth. The inertia and relative acceleration is the problem for neck tension and neck slippage. These big guns have relatively little force happening to the ammo. It’s the 500grn bullets in 9lb safari magnums that slam rounds around.