Variations in Die Dimensions among manufacturers

[PBSmith]

Recently I came into two sets of reloading dies for the same caliber (32 WS).

I notice that sizing cases in the RCBS dies requires noticeably more effort than sizing the same cases in a Lee die of the same caliber.

So I sent the ID prongs of my digital caliper into the two different dies and took readings at the same depth - about 5/8".

Sure enough, the Lee die is 0.0055" larger than the RCBS die at the point where I measured.

Is such a difference common? Is there any reason I should contact the companies?

Aside from measuring a FL-sized case and hoping for zero spring-back, I have no way of comparing to specs for that caliber.

Thanks
PBSmith

Edit: I lube cases with Imperial Wax - nothing to find fault with there.

[243winxb]

.4199" - .008" So, largest case body diameter is .4199" Smallest is .4119" SAAMI has a tolerance of - .008" This measurement is taken .220" down from the case head.

[MostlyLeverGuns]

No disrespect, but trying to measure inside diameters with dial calipers can be very tricky. A plug gauge or hole gauge can be more accurate. SAAMI specs for most cartridges are available online. The .32 WS has a wide cartridge body diameter that fails within SAAMI cartridge dimensions, so both dies may be within SAAMI specs. I have at 2 different sets of 32 WS dies. I will check the Sizing Dies for the dimensions using plug gauges or a hole guage.

[Walks]

I have 3 sets of .44-40 Dies. LYMAN from the early 1960's, RCBS from the mid 1980's and a HORNADY set from the early 2000's.
If you compare a sized case from each die set, they all look different. The LYMAN sets the shoulder further back then the 2 later die sets. I size only in the old LYMAN set. That way , rounds will fit in any old COLT SAA I care to shove them in.

All 3 sets flare the case mouths differently and crimp at different "depths" in the seating die.

When I bought my RCBS set back in the mid 1980's, RCBS stocked 2 separate die sets. One for Jacketed and one for Lead. I bought the one for Lead. I think that set became the Cowboy set. 20 years, and 20 years and 3 different Manufacturers.

You would expect closer tolerances.

[EDG]

I have measured a lot of dies. I currently have more than 100 die sets and many are duplicates of the same caliber but different brands. I also have several calibers with 2 to 5 duplicates of the same brand.

When you measure dies there are several things to keep in mind.
1. Measuring technique and measuring instrument. Calipers of any type are poor for measuring small inside diameters.
I used small hole gauges with good results. While kind of slow they gave excellent results. I later switched over to .001 increment gage pins. The gage pins gave the same results but are faster.

To measure the shoulder datum length of a bottleneck case you can use an optical comparator if you have access to one or you can use the Hornady tool.
The Hornady tool produces a small error unless zeroed with a gunsmith headspace gage.

2. When comparing one die set with another you should really compare FL sized cases. There are NO industry standard drawings or dimensions for dies, only for loaded ammo and chambers.

3. I have found several dies that varied a lot from each other.
These dies were probably made to incorrect proprietary drawings produced by the die manufacturer.

One was a Herter's 7X57 die that was so tight that it was nearly impossible to size a case without pulling off the rim.

The 7.65X53 Mauser is about the worst offender. All brands that I have tested were wrong except for RCBS. RCBS 7.65 dies are a perfect match to my rifle chambers. I have 4 rifles and 2 RCBS die sets. They are all the same correct dims.

I have 5 sets of RCBS dies in .35 Rem. I also have 2 CH die sets. All produce the exact same brass dimensions.

I have multiple die sets in 45-70, 40-65, 38-55, 9X57 Mauser, 8X57 Mauser. For the most part there is little difference in the die sets between brands or between multiple sets of the same brand.

For the BPCR rounds there are often variations to suited to jacketed or cast bullets. One set of my 45-70 dies sizes excessively but not so bad that I did not use them. They worked fine for 30 years.

[243winxb]

Measure the OD of a fired case. Size using the expander, measure . Remove expander, size again, measure. Note differences in OD. Most dies will over work the neck area.

Neck tension- measure the OD of a sized neck before and after seating a bullet. After seating , the neck should expand at least .002" to .004" for good neck tension.

Bushing dies give more control of necks. Redding Type S Fl sizing die works for me. The 32, may not be available?

[CamoWhamo]

I have 3 sets of .44-40 Dies. LYMAN from the early 1960's, RCBS from the mid 1980's and a HORNADY set from the early 2000's.
If you compare a sized case from each die set, they all look different. The LYMAN sets the shoulder further back then the 2 later die sets. I size only in the old LYMAN set. That way , rounds will fit in any old COLT SAA I care to shove them in.

All 3 sets flare the case mouths differently and crimp at different "depths" in the seating die.

When I bought my RCBS set back in the mid 1980's, RCBS stocked 2 separate die sets. One for Jacketed and one for Lead. I bought the one for Lead. I think that set became the Cowboy set. 20 years, and 20 years and 3 different Manufacturers.

You would expect closer tolerances.

I have tried 5 sets of 44-40 dies. Simplex, Lee, RCBS jacketed, RCBS Cowboy and Redding.

With the F/L dies the Lee are by far the largest. Cases sized in any other die literally drop into the Lee F/L die.

My Australian made simplex dies move the shoulder further back than any other brand. The RCBS and Redding have the shoulder way too far forward which results in short necked cases. The Lee is somewhere in the middle and just happens to match the chamber dimensions of my 3 (Miroku built) rifles so I use the Lee F/L die because it is working the brass less.

I gave up using the expander dies in all brands. They are all for .427 - .428 and my rifles take .431 bullets so i use appropriately sized NOE expander plugs for the Lee universal flaring die.

The seating dies are all different.
Out of the box the Lee would not allow seating of any bullets .430 and over, but the Lee die is soft enough that it was quick and simple task to hone out the seating die to take the larger bullets.
The RCBS also would not take larger bullets and the hardening in the die takes a long time to hone to size for larger bullets.
The Redding would take bullets up to .432 but the size at the case neck is tighter and it squeezes the case mouth and causes shaving of the bullet.

[MostlyLeverGuns]

I checked two 32 WS full-length sizers, a very old Herter's and a recent RCBS. The RCBS went .415 a quarter inch from the mouth using a pin gauge, the Herter's a little closer to .416. I would use the die that sizes the LEAST and still works to extend case life. I've got several .308, 300Savage, 35 Rem, other multiples, including Lee, some times Lee is tighter, sometimes looser, but I have not noticed any significant difference in cartridge fit in most rifles. I find using Redding Competition shellholders selected to set proper headspace is the best way to get accurate shoulder set-up with most dies.

[flashhole]

Interesting thread. Like others, I have many die sets but have yet to encounter the issues described by the OP. No problems to date that would cause me to dig deeper. I have seen differences in my 25-06 dies. Lyman dies exercise more of the case body than the Redding dies. I mix and match dies from different manufacturers for different cartridges based on target results.

[dragon813gt]

If no one else said it. Not only will there be varying dimensions among brands. You will have varying dimensions among different dies of the same brand. There are acceptable tolerances and if the dies fall w/in them then they’re shipped out the door.

[country gent]

Another aspect that is hard to measure but greatly affects the force to size a case is the actual finish in the die and or coatings used. I had a set of CH that appeared flash chromed inside that made to size 222 cases with almost no real force on the press handle. A few sets of titanium nitrate coated that were not bad for needed force to size cases. Had one set of dies that had a rougher looking finish and they were a bear to size with. I polished then up with some diamond compound on a patched dowel in the lathe and much better afterwards. I probably didn't remove .0004 total but the smoother finish didn't grab on the case.

Dies are normally cut to min specs minus a set amount to insure they size to fit any firearm out there, and any action type. Most dies size the neck portion of cases small and bring to size with the expander this makes any neck thickness of brass work. One reason the bushing dies are popular, brass isn't over sized. A min spec chamber needs brass sized accordingly to feed and function easily. Between dies shell holders different presses and brass variations its amazing there arnt more problems.

I started out loading with straight line dies ( lee and wilsons) first with a mallet then an old bottle capper then a small arbor press. I then went to 7/8 14 dies and a lee press. I have upgraded presses over the years and added them. And for some accuracy work I still use the Wilson dies and a small arbor press I made at work. Slower but works good and ammo is very good.

Measuring dies is best done with sized cases not just one but 10 and measure this helps eliminate any spring back issues. Or a cerro safe casting could be made and measured. CAse tapers can make getting a good reading tough at times though

[EDG]

As country gent mentions measuring cases can also be deceiving.
Several things can result in different case dimensions out of the same full length sizing die.
Those guys that do fast slam it up and pull it out of the die will get varying results.
To mostly eliminate case sizing variations try the following with bottlenecked rifle rounds:
1. Uniform amount of case lube every time
2. Slow sizing strokes with a 3 to 5 second dwell at full stroke
3. Multiple sizing strokes - try 3 or more and rotate the case about 1/3 turn between strokes.
4. Brass should be very clean and uniformly bright less heavy tarnish.
5. Brass should be of uniform temper. Anneal if required.
6.You need a 400 to 600 grit finish on the die inner surfaces.

You can be fairly certain of consistently sized cases if you check the head to datum length with a Hornady gage and there is only .001 to .002 variation over 100 FL sized cases.

[PBSmith]

Many thanks to everyone for your responses. Most of this is all new to me, and I appreciate the expertise shared here. I've got a couple of options on measuring and will be pursuing this further.