22-250 small base sizing die

2old2run · Dec 4, 2024

I'm considering building an AR platform in 22-250. Looking for a small base die set and see they are no longer made by RCBS. I don't want to be married to factory ammo if I go this route. Does anyone have any experience with this type of setup? Just curious.

It would be hell if I had to go the bolt gun route, lol.

ShtrRdy · Dec 4, 2024

Have you figured out how you're going to stack 22-250 cases in a magazine?

CK1.0 · Dec 4, 2024

Pick up a Lee .45ACP U-die small base sizing die and pull out the guts, voila, 22-250 (or any other .308-sized case head case) small base die (~$20).

It won't touch/bump your shoulders or necks, so you'll also/still need to use a 22-250 sizing die, but the Lee .45 U-die is just a carbide sizing die for a straight-walled pistol case, so it'll take care of the base of the cases for you.

memilanuk · Dec 4, 2024

CK1.0 said:
Pick up a Lee Factory Crimp Die in .45ACP and pull out the guts, voila, 22-250 (or any other .308-sized case head case) small base die (~$20).

I've heard this recommendation before... I already have a 'ring' die, so I don't really need another. Just out of curiosity... what does the ID of these dies actually measure? What do the cases actually measure @ the 0.200" line coming out of one of those?

CK1.0 · Dec 4, 2024

memilanuk said:
I've heard this recommendation before... I already have a 'ring' die, so I don't really need another. Just out of curiosity... what does the ID of these dies actually measure? What do the cases actually measure @ the 0.200" line coming out of one of those?

I actually edited my post while you were typing... I misspoke, it's the .45ACP U-die small base sizing die (NOT the Lee FCD) that does the trick. IDK what the ID is exactly, but it works. A .45ACP case OD is .476", using the U-die (-.003") you get .473" (same as a .308).

Lee Undersize Carbide 45 GAP, 45 ACP Small Base Sizing Die

Lee U Carbide Undersized Sizing Dies are great for reloaders looking for ultimate feeding reliability in their handgun. These dies undersize brass...

www.midwayusa.com

memilanuk · Dec 4, 2024

Then I don't see how that would actually work, in practice.

Most of my 'direct' experience is with .308 Win, as that's what I shoot in F-TR. Somewhere a few tenths north of 0.471" is where things start getting 'sticky'. Most small base dies squarsh it down to somewhere in the low 0.470 range. My 'ring' die is set for a 0.468" ID, which between spring back and whatnot, usually yields something in the range of 0.469" at the 0.200" line - and pretty much all the way to the extractor groove.

0.473" ain't gonna do it.

CK1.0 · Dec 4, 2024

memilanuk said:
Then I don't see how that would actually work, in practice.

Most of my 'direct' experience is with .308 Win, as that's what I shoot in F-TR. Somewhere a few tenths north of 0.471" is where things start getting 'sticky'. Most small base dies squarsh it down to somewhere in the low 0.470 range. My 'ring' die is set for a 0.468" ID, which between spring back and whatnot, usually yields something in the range of 0.469" at the 0.200" line - and pretty much all the way to the extractor groove.

0.473" ain't gonna do it.

IDK, YMMV. I had a buddy having trouble with a new 6CM gasser and the U-die did the trick (I can't remember what the before/after measurements were, sorry).

For ~$20, it's worth a try...

supercorndogs · Dec 7, 2024

Does RCBS still make the X-die FL die. It was a small base die also I believe.

2old2run · Dec 7, 2024

I see they still do. I was under the assumption that they were to minimize trimming. I do have x dies in several other calibers, but they also are specific as being small base.

I was mainly looking for a shooter. And ran across the 22-250 upper from Bear Creek Arsenal. After doing some reading about these, I'm reluctant to pursue.

I put a Howa together about 8 years ago in 223 remington, using a boyds stock. It was a good shooter on prairie dogs in south Dakota. Might just try that again in 22-250.

45-90 · Dec 7, 2024

I never needed a small base sizing die to run any 308, 6.5 CM, or 300 Ruger Compact Magnum, even with the max loads I run in the AR 10. Just regular FL dies work fine for a variety of autos, barrel lengths very firm 16" to 24" with most 18".
Many utilize the 6.5CM small firing pin dual ejector called "high pressure bolt".
One even has a magnesium upper with a titanium carrier, I just use regular sizing dies.
Try them first to see if ya even have a problem.

918v · Dec 7, 2024

Use standard dies and if they don’t size the base small enough for your chamber then use a 308 small base die with the guts removed in conjunction with your 22-250 dies. My RCBS small base 308 die will get the bases down to .468”.

45-90 · Dec 7, 2024

In reality it's not as it appears.
Most of the solid head portion of the case is not touched by any sizing die.
Because you have a shell holder and its thickness plus the lead in radius or champher on the die.
Mostly one sizes the portion just above the sold head where the real case expansion takes place.
Then part of the solid head is not supported by steel of the chamber.
If it expands the primer falls out.
You can not size what your die can not reach.
And you definitely are not reaching into the solid head
1 st pic 308 factory win chamber, notice there is no support over most of the solid head portion of the case. It could be .480" here and still chamber ...only the bolt .480 diameter goes over this portion of the .470" case head. If it expands .001" or .0015 " here your primer falls out.
The expansion mainly takes place above the solid case head where brass is thin.
Next pic here are some modified dies to make 308 into 35 Rem.
The shell holder is thinned and under cut to accept the thin silver brazed carbide ring extending from the special die. All undercut to fit inside the shell holder.
NOTICE when fully in max sizing position it still does not size maybe .030" of the solid case head. So its put in a lathe collet and turned down to size, as the case rim has to be cut down anyway.
So your factory dies do not even come close to fully sizing the solid head.

Next pic, this it the home built die to fully size the whole case...notice it meets resistance where most sizing dies do their work...this ia a real full length case sizing die...the whole case solid head and all, but does not touch the shoulder and neck.
You do not do this on a reloading press, but an arbor press.
Lube and size like using a bullet sizer.

These sizing problems are a mismatch between the rifles chamber and full length die, with tolerance stack up between the two, surface finishes, etc and even differences in brass cases and their hardness. I have a bunch of different 308 dies, maybe 8, each sizes a bit different. None are small base, but one Hornady die in particular oversizes the brass, but it does not reduce the solid head dia because it can not reach it...as shown.

2old2run · Dec 10, 2024

45-90 said:
In reality it's not as it appears.
Most of the solid head portion of the case is not touched by any sizing die.
Because you have a shell holder and its thickness plus the lead in radius or champher on the die.
Mostly one sizes the portion just above the sold head where the real case expansion takes place.
Then part of the solid head is not supported by steel of the chamber.
If it expands the primer falls out.
You can not size what your die can not reach.
And you definitely are not reaching into the solid head
1 st pic 308 factory win chamber, notice there is no support over most of the solid head portion of the case. It could be .480" here and still chamber ...only the bolt .480 diameter goes over this portion of the .470" case head. If it expands .001" or .0015 " here your primer falls out.
The expansion mainly takes place above the solid case head where brass is thin.
Next pic here are some modified dies to make 308 into 35 Rem.
The shell holder is thinned and under cut to accept the thin silver brazed carbide ring extending from the special die. All undercut to fit inside the shell holder.
NOTICE when fully in max sizing position it still does not size maybe .030" of the solid case head. So its put in a lathe collet and turned down to size, as the case rim has to be cut down anyway.
So your factory dies do not even come close to fully sizing the solid head.

Next pic, this it the home built die to fully size the whole case...notice it meets resistance where most sizing dies do their work...this ia a real full length case sizing die...the whole case solid head and all, but does not touch the shoulder and neck.
You do not do this on a reloading press, but an arbor press.
Lube and size like using a bullet sizer.

These sizing problems are a mismatch between the rifles chamber and full length die, with tolerance stack up between the two, surface finishes, etc and even differences in brass cases and their hardness. I have a bunch of different 308 dies, maybe 8, each sizes a bit different. None are small base, but one Hornady die in particular oversizes the brass, but it does not reduce the solid head dia because it can not reach it...as shown.

Appreciate all of your info and time!

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