Sierra Match King HPBT - asymmetrical?

[the naked prophet]

I ordered some Sierra Match King HPBT bullets for reloading (.308" dia) and I noticed upon inspection that the hollow points were not uniform or symmetrical. The tip looks like it was cut at an angle or something. Up to a 45 degree angle from normal to the bore axis. Is that not a big deal or what?

 

[ocabj]

The meplats, which are the tips of open tip match bullets such as the Sierra Match King, are not perfect.

Tool makers came up with meplat uniformers so you can uniform the meplat with respects to the ogive on your bullets.

Sinclair makes one. I think one is sold under the Tubb name, too.

 

[Grump]

Since I got identical accuracy with the irregular meplat/hole Sierras as I did with the Hornadys with perfect-looking holes, I don't worry about it.

I think it was the great barrelmaker Harry (?) Pope 100 or more years ago who experimented with lots of barrels and lots of bullets and determined that a nose must be really seriously boogered before it affects accuracy inside 200 yards. Beyond that, IIRC, you could get a bit more drop from a teensy bitta extra drag.

Damaging the heel of the bullet, OTOH, was guaranteed to open up groups sizes way quick and quite a lot.

 

[MTMilitiaman]

Yeah Grump is right. The nose really doesn't have a whole lot of influence on accuracy unless it is really FUBAR. It is the base of the bullet that needs to be perfect. Even minor dings the base of a bullet will have a much larger derogitory impact on accuracy than much larger imperfections in the nose. For example, shooting conventional soft points in a magnum bolt rifle will often result in the tips being bent and deformed as they slam against the inside of the magazine. This effect is only increased if it is a blind magazine that requires the rounds to be cycled in order for the weapon to be cleared. I've shot a bunch of such rounds in various weights and in different calibers, but never found deformed tips to have a noticeable influence on accuracy.

 

[musher]

FWIW

Harold Vaugn examined the effects of bullet tip deformation on accuracy in 'Rifle Accuracy Facts' pp 216-217.

The actual effect was too small to measure experimentally. Trajectory simulations (6 DOF) done with a 45 degree slice taken off the tip of a 150gr .270 soft point bullet to simulate tip deformation of a hunting bullet predicted an increased dispersion of .135 inches at 100 yards. It would be hard to see this in a 1 moa rifle.

Typical deformation seen in HPBT match bullets resulted in a predicted increased dispersion in the 3-5 mil range (.003-.005 inches).

 

[iamkris]

I was worried about that as well but...

My 7.62x51 mm loads (IMR4895 and 168 gr SMK) will easily do .75 MOA through a Springfiled Armory M1A Loaded.

My 5.56x45mm loads (Varget and 77 gr SMK) will easily do less than .5 MOA through a Hollinger-built DCM AR.

I ain't touchin' the meplat.