Jacketed Bullets in a Rimfire Barrel?

[Fox]

I thought the guys in the gunsmithing group would know.

I have a 25 rimfire, I am making ammo by trimming down 17 WSM cases, dumping the powder and putting in some powder then a 50ish gr bullet.

I wanted to know though, the standard 25 Stevens was a 65gr lead bullet, would it be safe to try a 65gr jacketed bullet? There are 0.257 65gr bullets, I have a sizing die to bring them down to 0.251 for this.

The rifle is a Cooey.

I know there are lots of people who convert 25s to shoot 25 ACP, which is a jacketed bullet but I do not know if that is a good idea.

Thanks

 

[NorthCoastBigBore]

Fox, I presume you slugged your barrel? Asking because my Favorite (not a Cooey) actually slugged out to .257" I'm running .259" lead bullets from an OTC Lyman mould.

I have seen similar reports from others on castboolits and here, might be worth confirming before you go too far down the path.

 

[Fox]

Fox, I presume you slugged your barrel? Asking because my Favorite (not a Cooey) actually slugged out to .257" I'm running .259" lead bullets from an OTC Lyman mould.

I have seen similar reports from others on castboolits and here, might be worth confirming before you go too far down the path.

I did not slug it all the way but I have 0.257 71gr cast soft bullets and some 0.251 50gr cast bullets. The 0.215 grabs the rifling for sure, the 0.257 seems like it would be really tight.

I know some people have said they use a 0.257 bullet but nobody with a Cooey has said that. Grandpa used to use the factory ammo and would get great accuracy. I just checked a factory bullet, hmm, they are 0.257.

So if jacketed would be ok then factory 60gr or 65gr 0.257 should work.

 

[NorthCoastBigBore]

I did not slug it all the way but I have 0.257 71gr cast soft bullets and some 0.251 50gr cast bullets. The 0.215 grabs the rifling for sure, the 0.257 seems like it would be really tight.

I know some people have said they use a 0.257 bullet but nobody with a Cooey has said that. Grandpa used to use the factory ammo and would get great accuracy. I just checked a factory bullet, hmm, they are 0.257.

So if jacketed would be ok then factory 60gr or 65gr 0.257 should work.

OK just thought I better mention that so you're not wasting time in the wrong direction.

I've always wanted to try this with a Cooey.

 

[Potashminer]

I can not help about the jacketed business - but a bullet should be "very tight" - to the point of possibly swaging down .001" or so when going up the barrel - is definitely to be preferred to an "easy fit" bullet that you can press in by hand - unless you are relying on the thing to "swage up" on firing?? I am facing similar - I have a properly chambered BSA in 270 Win - the bore is .270" but the grooves are .282" - so grooves are .005" oversize to normal 277" 270 bullets - my last "faint hope" is to try some Nosler Partitions - hoping that open rear end will "bump up" for a tight fit. Multiple conventional based bullets produce 4" and 5" groups at 25 yards - so about useless, as it is ...

 

[Fox]

OK just thought I better mention that so you're not wasting time in the wrong direction.

I've always wanted to try this with a Cooey.

Ok, I do not have a rod small enough to slug the whole bore. I took one of the 0.257 bullets and hammered it about half way into the muzzle, very good rifling on it. The largest diameter is 0.251in, the smallest is 0.245in, so this is a 0.251in bore for sure.

 

[Potashminer]

Fox - perhaps pick your words - if pounding a bullet part way into muzzle counts as "slugging" (I am not sure that it does, but what do I know??) - then you have .245" bore and .251" groove diameters. Is "normal" to use jacketed bullets at or slightly larger than groove diameter - but also has to do with dimensions at chamber end - the space for case neck holding that bullet, and the "ball seat" diameter. As you probably know, should be able to slip in a bullet into a fired case mouth - no resistance - that shows the case neck had room enough to expand under pressure and "let go" of the bullet.

 

[mac100]

It will work. I just did the same thing with a Remington #4 in 25 Stevens. I size 257 leaddown to 252 after powder coating. I converted mine to centerfire and modified 22 hornet cases to work.
It will also shoot 25ACP jacketed rounds.

 

[Fox]

Fox - perhaps pick your words - if pounding a bullet part way into muzzle counts as "slugging" (I am not sure that it does, but what do I know??) - then you have .245" bore and .251" groove diameters. Is "normal" to use jacketed bullets at or slightly larger than groove diameter - but also has to do with dimensions at chamber end - the space for case neck holding that bullet, and the "ball seat" diameter. As you probably know, should be able to slip in a bullet into a fired case mouth - no resistance - that shows the case neck had room enough to expand under pressure and "let go" of the bullet.

Slugging is normally down the whole length of the bore but I do not have a rod long enough for that, so hammering a soft lead slug half way into the bore from the muzzle seemed to work.

Yes, 0.251 bore, 0.245 groove, so a 0.251 bullet is what I should be targeting.

I am just trying to find something heavier than 50gr, closer to the factory 65gr.

 

[Fox]

It will work. I just did the same thing with a Remington #4 in 25 Stevens. I size 257 leaddown to 252 after powder coating. I converted mine to centerfire and modified 22 hornet cases to work.
It will also shoot 25ACP jacketed rounds.

So no issues with increased pressures into the dangerous range with jacketed bullets?

I found a number of people who are loading 25-10 and cut down 17 WSM into their 25 rimfires and converted centerfires, they seem to agree on 1.9gr of Win 231 (HP-38) with a 50-70gr bullet.

 

[mac100]

So no issues with increased pressures into the dangerous range with jacketed bullets?

I found a number of people who are loading 25-10 and cut down 17 WSM into their 25 rimfires and converted centerfires, they seem to agree on 1.9gr of Win 231 (HP-38) with a 50-70gr bullet.

I have never tried the 17 WSM cases. The conversion to centerfire was much easier and the Remington #4 rolling block is pretty strong. I don’t think I would trust a falling block Stevens though.

 

[Longwalker]

Fox, some writing on the topic of jacketed vs cast bullet pressures by gun writer John Barsness reveals that "usually" jacketed bullets actually produce lower pressure than cast, presumably because there is little or no "swaging" or bump up of bullet diameter upon firing. Does not apply to monometal bullets and some very hard steel jackets, but is a reasonable thumb rule for standard cup and core bullets. Wear to the soft steel of the bore might possibly be an issue though. Many rimfire files were made with quite soft steel because the rimfire bullets put so little stress on them.