Undersizes 25-20 - ideas?

Dark Alley Dan

Dark Alley Dan

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Howdy, braintrust. An interesting problem has arisen, and I'd appreciate your ideas regarding a solution.

Bought a sweet little Belgian Martini chambered in .25 Stevens Rimfire, and thus unshootable. But it's such a lovely trim little thing I couldn't stand not shooting it, so I had my guy rechamber it in 25-20.

25-20 throws bullets c. .257 in diameter. 25 SR is happier with .252/.253. I'll only ever shoot lead in this old lady. But squeezing bullets around .004 oversize down that bore seems risky.

I've accessed some 60 gr. 252 slugs from Prairie Projectiles. They'll work well for what I'm doing, and were reasonably priced. But here's my problem - they drop clean through the neck of a 25-20 case. They won't hold still to be crimped in place. I'm thinking a little dacron in there to make up the volume and hold the bullet at the right height, but unless I figure out exactly how much to put in, I'm going to see variations in OAL that I don't want.

I could partially crimp the cases prior to seating, but man, that seems a lot of dinkin' around, and getting it exactly right is gonna be a bear of a job.

Ideas? Am I being too cautious (if such a thing is possible)?

Thanks in advance for your wisdom. And Happy New Year!

Dan
 
If the .257 bullets when loaded in brass chamber in the gun without resistance it would be fine to shoot lead bullets of that size out of it.

Or you can buy a sizer die and size the .257 to .255

Or try removing the deprimer from your resizing die and then size your brass brass. Often they are what expands the brass to proper size and without it the brass will be under size on the neck diameter. if you still want it to deprimer just put it in a drill and sand/grind more then 0.005" off the thick part of its body
 
No it won't often you want lead bullets to be 0.002" bigger anyway to help stop leading. And you will be reloading I assume, just start low and work up. Pressure = velocity (well that's not a blanket statement I understand pressure curves and things like peak pressure, but in this case it's the same powder) so if it's building a bit more pressure you will just get the same velocity with a slightly lesser charge.

The main thing is the loaded round has to chamber with our any resistance, there needs to be a little room for the neck to swell to release the bullet. It's somethings call " the plunk test" the round drops in with a plunk sound
 
I agree with the larger lead bullets won't hurt a thing. do you have any photos of the rifle? and wondering that your gun guy charged you. I want to pick up a Stephen's favorite and have it rechambered for 32 s&w
 
Yup, the first step is to remove the expander plug on the priming stem, resize a case, and see how tight the resized neck is. Might be all you need. But I'd be happier starting with a bullet 0.002" over groove diameter.
If you slug your bore and your grooves measure .253", and you size a bullet .255" for proper bore fit, it's realistic to think your present loading die should work OK if you don't expand the case neck as described above.
 
The small sample of 25rf ammo I've measured has bullets at 0.255-0.256" so you should be fine. I would be interested to know what the groove diameter of the average 25rf actually is as I suspect the 0.252" that's often quoted isn't actually what most guns are.

The Martini is also a strong action for its size with people rechambering them for 357Magnum and 222rimmed.
 
I personally wouldn't worry about shooting the larger bullets as long as they chamber easily. Unless you were loading some really hot loads I don't think you have anything to worry about. I've shot cast bullets that are similarly oversized in a few different rifles with no problems.

Chris.
 
Thanks, fellows. I don't plan on trying to duplicate 25-06 ballistics here. :) Just wanna roll some cans around, maybe whack a couple gophers when spring comes.

Very much appreciate the advice. I'm walking new country here and value your experience.
 
'Smellie' ( RIP) threw this one my way years back. Cut a small piece of cardboard out of a Corn Flakes box ( or the cereal of your choice), it won't be square due to the tapered case. You'll have cut a few to get it right
Interweb says it is an Isosceles trapezoid ( Yeah, I had to look it up), roll it tight and insert it into the case. It's memory will expand it, if you cut it right...it'll expand to the inside of the case with no 'Break' or 'overlap'
It'll be a little trial fitting to get it right, it came from some version of 577 SE. Easier with a big case...but still a valid concept.
Fills the case a touch, but if the length is right....it'll be a perfect little ledge that your bullet will sit on.
Then run it up into the die and crimp it.
The diameter would be fine IMO, the single shot is pretty forgiving as far as crimping...as long as you are short of the rifling leads...you won't need too much crimp.
If you find the trick works...the same piece of cardboard works for a few reloads. If you have to get it out every time, the suck will be kinda large.
 
Thanks, fellows.

It would seem that the gist of what I'm hearing here is that I shouldn't worry too much about squeezing .257 bullets down a bore designed to work with .251 bullets. That being said, I'll pull the expander and see if I can make the hundred .252 slugs I have work in some capacity.

Cheers!
 
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