Bullet run out how much matters?

[Uncle Ed]

"a full-length sized case in which the neck is also fully sized. There is clearance at the neck and in the body of the case, the closest fit anywhere is the bullet in the throat. If the neck to bullet concentricity is good (although it needn't be perfect), then the bullet will find good alignment in the throat and the case body and neck will have minimal influence. Let's not forget that the base of the case is supported by the bolt face or the extractor to a certain degree as well; this is yet another influence on alignment. As you can see, there are several points from base to bullet that can have an effect. My procedure is to minimize the influence of those that I can control, namely the case body and neck, and let the alignment be dictated by the fit of the bullet in the throat and to some extent by the bolt's support of the base. Barring a seriously out of square case head, I don't think the bolt can have a negative effect on alignment, only a slightly positive effect from minimizing "case droop" in the chamber. Given that a resized case will usually have a maximum of 0.001" diametrical clearance at the web, this isn't much of a factor anyway.

In conclusion, I believe that allowing the bullet to find a relatively stress-free alignment in the throat by full length sizing (including the neck) and turning necks to enhance concentricity gives the bullet the best probability of a well-aligned start into the rifling."

The Rifleman's Journal
Germán A. Salazar

 

[Bart B.]

"As you can see, there are several points from base to bullet that can have an effect."

He left out the major contribution to repeatable neck and bullet alignment to bore center. Smart folks know what it is.

 

[oldroper]

So, is Bart B. replacing the missing F. Guffy?

I think it uncle ed,

 

[Uncle Ed]

I think it uncle ed,

You wouldn't of said that if you knew that Bart B. said Chesty Puller was a Navy cook.

 

[Bart B.]

You wouldn't of said that if you knew that Bart B. said Chesty Puller was a Navy cook.

The needle on your stupid meter just pointed higher.

 

[jimmymac]

God Bless us, everyone!

 

[oley55]

You wouldn't of said that if you knew that Bart B. said Chesty Puller was a Navy cook.

he better had not!

"Good night Chesty, wherever you are."

 

[Bart B.]

You wouldn't of said that if you knew that Bart B. said Chesty Puller was a Navy cook.

He really was. We told him to do his best over the 3 daily meals his first day aboard. He did so we gave him a little star for each one. Then had him serve shiverin' Liz in a snow storm for dessert, clean the scullery then feed out pet sea bat.

 

[INTJ]

The best course of action is to not use any expander ball in a sizing die at all. Forster hasnt figured out any magic there- it still plows an expander back thru a case. They just put it in a different place to make you think it must work better (but it doesnt)

I used to remove all my expanders, but now I only remove expanders when using bushing dies, and I only use bushing dies for neck turned cases.

A neck turned case is consistent in thickness so as the bushing sizes it down its the same diameter inside as outside.

An unturned case is not the same thickness. So if you don’t have an expander ball, all the irregularities are transferred to the inside of the neck when the necked is sized smaller. The bullet is then seated into a neck of irregular inside shape.

When an expander ball is used, the irregularities are transferred to the outside of the neck so the bullet is seated against a consistent surface. In a typical non-neck turned chamber, there is enough clearance so that the irregularities on the outside of the neck aren’t a problem.

Not sure any of this makes any difference on paper.........

 

[oldroper]

You wouldn't of said that if you knew that Bart B. said Chesty Puller was a Navy cook.

You got lot class talking about combat marine.

 

[INTJ]

But what is acceptable to sierra?

IIRC, 1.1” 10 shot groups at 200 yds from their rail gun type setup. But don’t quote me on that........

 

[Uncle Ed]

You got lot class talking about combat marine.

oldroper

Bart B. is retired Navy, you are a Viet Nam Marine Vet. I was just trying to better relations between a squid and a jar head.

I hope you don't mind having a squid telling you all about the M14 rifle, and how to play with your gun.

 

[Falfan2017]

We were messing around in my shop tonight and thought we would run a concentricity test. Took two pieces of the very same brass that had been neck turned and fired the same amount of times and ran one in the Redding f/l sizer and the other in the lee collet die then ran them on my Sinclair concentricity gauge. Both came out right at .001. The only differents we could see is the Lee is only $30

I got a 30$ hornady fl, whidden and a few Harrels. All seem to produce similar runout numbers lol.

 

[Richard Coody]

quite a discussion.

probably why jamming into the lands is so common in benchrest.

i worked for a solid year learning about concentricity and neck tension and their effect on accuracy. my test bed was a 6br that consistently shot in the 2's.

i found by soft seating in the lands with berger vld's groups were consistent.

i found my best groups by selecting loaded rounds with zero runout and seating pressure consistent within 10#. using 21st century concentricity gauge and 21st century hydro press.

question is is it worth all the effort for .03 to .05 improvement in group size? only you can decide.

 

[dkhunt14]

Question is is it worth all the effort for .03 to .05 improvement in group size? only you can decide.

I believe it is more important in longrange. At 1000 yards you can lose by that .03 or even less. In the last 10 years, things improved and the competition is so tight. I have shot some very bad runout in some sets. I shoot in the lands and it didn't seem to shoot worse. I believe the throat straightens them out. Matt

 

[Ccrider]

That is what I was wondering about. How can the small amount of bullet runout not be straightened after spinning through the barrel?

 

[Richard Coody]

That is what I was wondering about. How can the small amount of bullet runout not be straightened after spinning through the barrel?

my thoughts are if you are jumping a bullet and it hits the throat and rifling at an angle then it will probably imprint into the rifling with the nose of the bullet slightly skewed. how much it effects accuracy can only be seen on the target.

if you are jammed most likely the bullet is squared up on chambering.

 

[Bart B.]

Bart B. is retired Navy, you are a Viet Nam Marine Vet. I was just trying to better relations between a squid and a jar head.

Those relations were great after an incident aboard a battleship. The fleet marine detachment GySgt walked into the CPO quarter's head to relieve himself. The navy CPO next to him finished and started for the exit door.

The Gunny says "Hey, Chief, aren't you gonna wash your hands?" The CPO replied "Don't need to, Gunny. Sailors cannot leave boot camp until they learn how to not pee on their hands.

The Gunny replied with a smile then said "That's good. Let's go to the club next time in port and I'll buy you a couple.

 

[Bart B.]

IIRC, 1.1” 10 shot groups at 200 yds from their rail gun type setup. But don’t quote me on that........

All Sierra match bullets must test inside 1 inch at 200. Used to be 1/2 inch average ES at 200.

 

[oldroper]

oldroper

Bart B. is retired Navy, you are a Viet Nam Marine Vet. I was just trying to better relations between a squid and a jar head.

I hope you don't mind having a squid telling you all about the M14 rifle, and how to play with your gun.

I know about combat, I was with 4th Marines when we landed at Chu Lai. As far as Bart goes he's not combat vet. I really don't find that funny