Sizing Die Adjustment - Needed??

[bigedp51]

Bitis Arietans

When I got out of the military in 1973 I bought a Remington 760 pump and a Lee loader. The third time I reloaded and fired the cases they would not eject until the cases cooled off.

What I'm getting at is a case needs to be small enough in diameter after sizing to spring back from the chamber walls and extract. This amount varies but a bolt action should be able to get by with less than needed for a semi-auto.

A small base die will make the case diameter .002 to .003 smaller than a standard die. The small base die will also push the case shoulder back a additional .002 to .003 than a standard die. And many people who think they need a small base die end up having case head separations because of excessive shoulder bump. Meaning too much head clearance or "air space" between the rear of the case and the bolt face.

Bottom line, find out what the problem is before buying a small base die. I have small base dies and they are used to size once fired military Lake City brass "once" to bring these cases to minimum SAAMI dimensions. Thereafter I use standard dies to size this brass fired in "my" chambers. And when using these small base dies I'm using Redding competition shell holders that push the case .004 "LESS" into the die than a standard shell holder.

Example if I used a standard shell holder with my small base .223 die it can push the case shoulder back .007 from its fired length fired in my AR15. And these cases would be very short lived and seperate after very few reloadings.

You need to measure a fired cases diameter and the cases headspace length and see if the die reduces the case dimensions enough to chamber.

In a semi-auto the case diameter needs to be .003 to .005 smaller than its fired diameter for reliable extraction. And your problem as stated is not a extraction problem. My guess is lapping the shell holder should fix your problem.

 

[JTB]

Quickly read through this thread and I have had a problem similar to this in the past. It sounds like the brass belt is binding in the chamber. If you don't mind destroying one case try grinding off the belt and see if it loads easily. If it does you will know it needs to be chambered in another 2 thousandth or so.

 

[Bitis Arietans]

Big E

RCBS's website warns not to use the Small Base Die for a Bolt Action...it didn't say why, but you did!

I called them back, and questioned this. The Tech said that he's used these die for the express reason that I explained (as well as his colleagues)..and he spoke with some "head tech", previously and it is acceptable to RCBS.

That said, I must proceed cautiously. I fully understand your explanation...thanks again for the graphics!

Did some reading about case head separation. So if I understand it...I'll explain what I think it is:
The cartridge should fit into the chamber like "hand to glove". Upon firing, the cartridge case should really go almost nowhere (have very little room to move) except toward the muzzle, within the chamber. The projectile is the only thing that can move, and blah, blah, blah,...

I found the following on the web"
Do I have this right, Ed??

Case Head Separation (and how to avoid it ... )

This picture shows the first sign of case head separation on two fired .308 Winchester cases. Notice the bright horizontal ring near the base of these cases. This is a common problem for handloaders, when cases don't get resized properly. Avoiding this symptom often means going beyond just reading the instructions that come with resizing dies. Case head separation is caused when the case shoulder gets pushed back a few thousandths of an inch too far during the resizing operation. If you measure your cases (at the shoulder), this can be avoided by setting your die height more accurately.

​

If you ever experience this warning sign of case head separation take it seriously, and throw those cases away. The next firing would definitely split these cases in two, leaving most of the case stuck in your chamber. The escaping gases can blow back through the bolt, and cause serious injuries.

If you handloads have no chamber clearance (at the shoulder), your handloads might not chamber properly. If the case shoulder gets pushed back too far, your handloads will be too short for your chamber. When a short case is fired, its shoulder is blown forward until it fills up the chamber. This stretches a case just above the web (the solid part of your case). At this point the case becomes paper thin, and it's wasted. These cases could have been used for many more loadings if they had been measured and accurately resized at the shoulder during the reloading process.

What followed on the web was an advertisement for a Digital Head Space Gage made by "Innovative Technologies"
I should have the Hornady Lock-N-Load Headspace Gauge 5 Bushing Set with Comparator, the RCBS Precision Mic 7mm Remington Magnum, and a new shell holder in a few days.

 

[rcoody]

First firing it headspaces off the belt and expands to fit the chamber. Subsequent loadings should headspace off the shoulder. Simply set your die up for a .001 shoulder bump or neck size until round.won't chamber.

Sometimes one.firing will not fully fireform a case. Might see more growth on the second.firing.

That pressure ring just above the belt causes chambering problems. If you don't like the.small base dies you might try this

Reloading Belted Magnum Calibers

 

[Bitis Arietans]

Hey RC

I'm just learning that there is more than the "instructions" included with the sizing die.
...and just understanding 'bout the shoulder bump...so I'm somewhat embarrassed to admit: "I don't know how to set the die to produce the .001" shoulder bump."..I didn't know what a "bump" was until 3 days ago, and that I was really just loading, the somewhat equivalent to "store-bought" "boxed" ammo. Duh....But I am learning
!
In my "limited" world, I've just set the FL Sizing Die to the top of the shell holder, screwed down the die - -1/8 to 1/4 turn, and away I go!

NOT SO! If you want truly custom ammo! As I do. There's more to it!

So, to recap, so you don't need to look back...

• I started w new brass, in a friend's 7MM RM,
• shot,
• FL sized the brass like I always do, setting the FL Sizing die 1/4 turn DOWN, snugging up the die and shell holder,
• loaded, found the cartridges were tight in the chamber,
• shot them,
• FL Sized, and before loading them checked them in my bud's rifle, TIGHT AGAIN,
• checked them in my 7MM, NO PROB.

Dumbfounded!

I have some work to do, before I make any conclusions as many have pointed out..

• start w/ new brass again
• after firing, check to see if new brass will chamber in this rifle
• take head space measurements, to see where the issue truly lies

 

[WildRose]

Hey RC

I'm just learning that there is more than the "instructions" included with the sizing die.
...and just understanding 'bout the shoulder bump...so I'm somewhat embarrassed to admit: "I don't know how to set the die to produce the .001" shoulder bump."..I didn't know what a "bump" was until 3 days ago, and that I was really just loading, the somewhat equivalent to "store-bought" "boxed" ammo. Duh....But I am learning
!
In my "limited" world, I've just set the FL Sizing Die to the top of the shell holder, screwed down the die - -1/8 to 1/4 turn, and away I go!

NOT SO! If you want truly custom ammo! As I do. There's more to it!

So, to recap, so you don't need to look back...

• I started w new brass, in a friend's 7MM RM,
• shot,
• FL sized the brass like I always do, setting the FL Sizing die 1/4 turn DOWN, snugging up the die and shell holder,
• loaded, found the cartridges were tight in the chamber,
• shot them,
• FL Sized, and before loading them checked them in my bud's rifle, TIGHT AGAIN,
• checked them in my 7MM, NO PROB.

Dumbfounded!

I have some work to do, before I make any conclusions as many have pointed out..

• start w/ new brass again
• after firing, check to see if new brass will chamber in this rifle
• take head space measurements, to see where the issue truly lies

It's not at all uncommon to have brass sized properly for on rifle and have it too tight in another. That's why most of us even if we have multiple rifles in the same caliber will keep the brass segregated for each of them and reset the dies for each of them every time we load.

It's a pain but it can save you a lot of pain and heartache.

 

[philipbrousseau]

Bitis, take a piece of your tight fitting brass and remove the de-cap expander spindel from the full length sizing die run the case through the die and see if it will chamber without resistance in s&w rifle.

 

[Bitis Arietans]

PB
Yes i will try that as soon as I get home...if it fits, what does that mean?
Thanks for your insight

 

[rcoody]

PB
Yes i will try that as soon as I get home...if it fits, what does that mean?
Thanks for your insight

He believes dragging.the expander ball up through the.neck of.ths.brass is.stretching the.case.out.longer.

One.of.ths.reasons.it is.very important to lube the inside of the necks when resizing cases. Dry graphite neck lubr like this
Imperial Dry Neck Lube Application Media 1oz

 

[Bitis Arietans]

Good Evening...My Friends at LRH

I'm not sure how to attach a photo, but...

I noticed, while lapping the shell holder that I have that it's NOT square on the surface that contacts the bottom of the FL Sizing die, it's tapered

 

[Bitis Arietans]

The pic on the left shows the shell holder that I removed material from...It was already tapered.

The other pic shows the taper holder and another holder (from a different cartridge).
It's "square" on the surface contacting the die (I checked a 3rd and it's also square)

The tapered one is a different brand than the 2 square ones.

That said, I removed more than .005" from the "high side" (new shell holder on it's way)

...And as many have told me...a FL sized case chambers perfectly!!! Volia!

So, I'll have to get another shell holder that I haven't cannibalized, ...small price to pay! ..and still have to take some head space measurement

What does this mean, NOW? What should be my next steps?