BUMPING THE SHOULDER

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  • Last Post 15 June 2012
joeb33050 posted this 13 June 2012

Some shooters neck size and now and again bump the case shoulder back a bit. I'd like to hear about what kind of neck sizing dies are used, (FL die backed out, LEE Collet, “Button” type Redding/RCBS/Wilson), how you know when to bump the shoulder, and how you bump it, what happens if you don't bump, and anything I've missed. Thanks; joe b.

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TRKakaCatWhisperer posted this 13 June 2012

I've used both Lee and Wilson.

Lee sometimes needs TLC (clean/lube).

Wilson sized 1/2way down neck (good in my book as bottom half helps center top of case to the chamber).

Must sort by brand or thickness of neck wall.

Prefer Wilson for PRECISON/ACCURACY, Lee for speed or when using other 7/8-14 dies.

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onondaga posted this 13 June 2012

http://www.castbulletassoc.org/view_user.php?id=3>joeb33050:

Joe, I use the Lee Collet Neck sizing dies in a bunch of calibers and have never needed to bump shoulders at all, ever. My brass never grows larger than the chamber from firing in any of my calibers. I never could understand why some people claim that this happens to them. My suspicion is that it is their firearms action fit changing  and not the  Lee Collet Neck Sizing Dies.

Gary

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billwnr posted this 13 June 2012

I've got two .30BR's. One needs periodic shoulder bumping and the other rarely needs it.

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TRKakaCatWhisperer posted this 13 June 2012

onondaga wrote: http://www.castbulletassoc.org/view_user.php?id=3>...I never could understand why some people claim that this happens to them. My suspicion is that it is their firearms action fit changing  and not the  Lee Collet Neck Sizing Dies.

Gary

It has NOTHING to do with the neck sizing.  Cast bullets generally won't do it - as the loads are most often mild; but with max jacketed loads the cases stretch.

 

 

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onondaga posted this 13 June 2012

http://www.castbulletassoc.org/view_user.php?id=3>joeb33050:

Joe, this is actually a hot and repeatedly disputed topic.

Neck thickness comes up with the discussion. Look at neck thickness' relation to neck sizing in this way: Fire some factory ammo, neck size  it and load it with your choice of bullet. If extracting the factory round in the first was easy and now after your reloading you have hard chambering, neck sizing is not the blame.

 The new bullet is different, Neck wall thickness reduction may compensate. But it could also be your primer seating depth that is causing hard chambering.

The Lee Collet Neck sizing Dies do not touch the slope of the case wall from the neck to the shoulder, they don't touch the shoulder either. The slope and shoulder fire formed dimension are retained with Lee Collet dies. So If you had easy extraction before reloading previously neck sized ammo and now you have hard extraction, You have distorted your brass in some other way than neck sizing it. Repeated cycles will not change this and make your brass suddenly grow longer at the shoulder.

Any rounds that do not extract easily should not be neck sized. Finding out the reason for hard extraction is the more important course. You can ignore a loose action and full size the problem brass to get it working again, but doing so ignores the source problem.

Neck sizing is only recommended for bolt rifles and single shot rifles when the ammo will always be used in the same fire arm. People neck sizing for semi-autos, lever guns and pumps are inviting problems because those actions are inherently loose to function with fully sized  or factory ammo. Those 'Loose ” actions will spit out brass with variances in case length to the shoiulder because of the inherent results of the action type. A bolt action with a slop fit of the bolt or lugs will do this, so will a single shot with a slop fit,  but the effect is much more minimalized with bolt and single shot firearms.

Gary

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pat i. posted this 13 June 2012

TRK wrote: It has NOTHING to do with the neck sizing.  Cast bullets generally won't do it - as the loads are most often mild; but with max jacketed loads the cases stretch.

 

  This. Joe a neck sizing die isn't going to bump the shoulder.

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TRKakaCatWhisperer posted this 14 June 2012

Add this to the mix:

Necked cases stretch more if the angle of the shoulder is low, as in 30-06 and stretch is much less as in the Ackley versions and ctgs like 6ppc, 6.5Grendel et al.

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joeb33050 posted this 14 June 2012

What I'm looking for is this info: Do you neck size cases, and on occasion have to set the shoulder back a bit? If no, stop. If yes, A. How/with what dies do you neck size? B. What tells you that it's time to set the shoulder back?

Thanks; joe b.

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TRKakaCatWhisperer posted this 14 June 2012

OK!

Yes, I neck size - lots of calibers. about 7 using Wilson, 2 or 3 using Lee.

When to set the shoulder back - when the case is long enough to cause difficulty in closing the action (falling block or bolt).

(I neck size for MOSTLY bolt/falling block actions - perhaps one or two semi.)

IFF the semi functions well with necksizing only (6.5 grendel) because of the shoulder angle and not given to stretching - then I'll neck size only.

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joeb33050 posted this 14 June 2012

Do you neck size any ctgs using a FL sizing die backed off a bit? How much resistance signals the need to set the shoulder back? Colose he bolt with finger and thumb? Must use palm to close bolt? What do you use to set the shoulder back, and how? Do you neck size for 308 Win and/or 223 Rem and/or 243 Win? Thanks; joe b.

TRK wrote: OK!

Yes, I neck size - lots of calibers. about 7 using Wilson, 2 or 3 using Lee.

When to set the shoulder back - when the case is long enough to cause difficulty in closing the action (falling block or bolt).

(I neck size for MOSTLY bolt/falling block actions - perhaps one or two semi.)

IFF the semi functions well with necksizing only (6.5 grendel) because of the shoulder angle and not given to stretching - then I'll neck size only.

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delmarskid1 posted this 15 June 2012

I have used full length dies to neck size. I backed off the die until I was sizing less than half of the length of the neck. When I did more than this I needed to lubricate the body of the case. When this happened I figured that I was no longer neck sizing. I don't remember which calibers I did this with.

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TRKakaCatWhisperer posted this 15 June 2012

Yes and no. I call using a fl die to neck size 'partial full-length sizing' because it just reduces some of the body a little. At some time I got a true neck sizing die and it allows a tighter fit of the body in the chamber.

I use the Wilson for .308, .223, 6.5G and several others. I think I've also got the Lee for .308 (have to look).

In my 40x (7.62 Nato) I like to JUST feel the resistance when closing the bolt with thumb and two fingers. Also I look for a SLIGHT burnishing of the base as the bolt turns on a fixed-in-the-chamber case. (Kind of like the feel of a part measured in a caliper.)

BUT (perhaps a bit off-this-topic) with .405 Win (straight case) there is no neck sizing die, so I partially full-length size - just enough so the two step expander will leave the two diameters so the bullet will slip in the first 0.1 or 0.2” and seating die push in the rest. Then the block (Ruger #1) will just push the cast bullet into the rifling. Perhaps 0.1” - any more and the bullet would not allow the block to close.

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