7.62x51 NATO bullet pull spen

[TheFalconeer]

Lads & Gents,

À friend of mine asked me what is the specifications for the minimum force of bullet pull for the NATO spec 7.62x51.

I know that I have the spec book somewhere but I can't find it now... Does anyone have the value on hand?

Envoyé de mon LDN-L21 en utilisant Tapatalk

[Humpy70]

I am in Myrtle Beach on vacation and don't have the specs with me but IIRC correctly the MINIMUM bullet pull on the M118 LR ammo is 10 lbs. As I remember there is no max pull. You can find ammo that has upwards of 300 lbs bullet pull so that is one reason why the SD on MATCH ammo is so high. The inside of the case mouth is coated with a lacquer that hardens with age as this is part of the waterproofing for ball and match ammo made to gov't specs.

Several things account for this, when match ammo is loaded it is checked for bullet pull and then sent to deep storage where it may sit around for years before it is shot.

Such is very evident if you get into downloaded match ammo as you will find quickly some will just come out easily and some you may have to grip several times to get it to release.

The military teams would take their match ammo and "bump" it by running it into a seat die, setting the bullet back .005 - .010 to "break the seal" and you can hear it when it loosens up.

Ball ammo can be a real bear to pull as it is not only lacquered, it is crimped into a cannelure. MATCH ammo does not have a cannelure as such is detrimental to accuracy.

If you pull the bullets with a collet puller you will note the black lacquer stays on the bullet mostly. When I pull down match ammo I dump the bullets in a cleaner I get at Home Depot and I fill a jar with bullets then pour in the solvent and let them sit over night and next morning they look brand spanking new.

Having a uniform bullet pull is the key to long range accuracy as the small the SD the less vertical dispersion you are going to see starting about 600 yards if you have a very good rifle. 1000 yard targets have a 20" 10 ring. 50 fps of dispersion vertical will give you a 20" group so what you need to strive for is ammo with a SD of like 10 or less.

[TheFalconeer]

Thank you for your feedback.

I looked in the MOPI and it state that a minimum of 256 Newton should be necessary for bullet extraction.

Envoyé de mon LDN-L21 en utilisant Tapatalk

[Humpy70]

It depends on what your game plan is. If you want feed reliability from a magazine you need to hold the bullet tighter. If you want absolute best long range performance you want the bullet seated so light that you have to ease it into the chamber and gently close the bolt to get the more uniform release from round to round.

[Bimmer]

I looked in the MOPI and it state that a minimum of 256 Newton should be necessary for bullet extraction.

Wow, that's ≈189ft-lbs!

[markm]

I didn't know that M118 LR had neck sealant. I assumed it didn't because we used pulled bullets that had no lacquer on them. Maybe they chemically removed it. ??

[Humpy70]

173 gr. Match bullets as pulled showing mouth lacquer residue


173 gr Match bullets cleaned

I get the degreaser at Home Depot in the chemical department. ZEP 505 and sells for 8.96 per gallon. Comes in gallon cans and you can reuse it several times.



Bullets soaking in ZEP 505. Note the lacquer falls off bullets intact and does not dissolve that much.

There were some lots run without sealant as the Army Marksmanship Unit requested they be run. The Match ammo with the 175 grain Sierra MKs did not have it.

When I pull bullets from new match I clean them up and reload them and when the case is fired it burns off what did not come out on the bullets.

[Steve Shannon]

Wow, that's ≈189ft-lbs!

I’m sorry to correct you, but that’s 57.5 lbs.

A Newton is a unit of force, specifically the force required to accelerate one kilogram at a rate of one meter per second per second.
Ft-lbs. is a measurement of energy.


Sent from my iPad using Tapatalk

[Humpy70]

I had a contact at Olin who told me he had seen ammo that took 300 lbs of pull to move bullet.

[Bimmer]

I’m sorry to correct you, but that’s 57.5 lbs.

A Newton is a unit of force, specifically the force required to accelerate one kilogram at a rate of one meter per second per second.
Ft-lbs. is a measurement of energy.

OK, I'll bite...

If its 57.5lbs moved a meter (3.28 feet), then isn't that 57.5lbs x 3.28 ≈ 189 foot-pounds?