357. 125gr LRNFP Question

[sjs]

Trying to load 125 gr. Missouri Bullet Co. LRNFP bullets in .357 mag cases with 5.0 gr. of HP38 for my SW 686 3". My published data states a COL of 1.580 for 125 gr. lead bullets but the longest I can get and still hit the crimping groove is 1.505, which is .075" shorter.

I would greatly appreciate it if anyone has some published data that would suggest this would be a safe load. I don't need a fast load, it is just for target shooting but I am concerned about spiking pressure by going to short on the COL.

Any comments are appreciated.

 

[Forrest r]

That 5.0gr load isn't even in the realm of 357mag pressures.

Heck hodgdon's cowboy action load data doesn't even list a oal

It states a MAX load for a "125gr lead rnfp" is 5.5gr of ww231/18,800cup
Same bullet/load data is 4.8gr in 38spl cases/16,900cup

 

[sjs]

Thank you.

 

[Nightowl]

I always crimp in the crimping groove. COL really only applies to heavy for caliber bullets where the length could be longer than the cylinder. Or lever action when functioning is important. Bullets around 170 grains should be checked for COL.

 

[ppeeks]

That's MAX COAL as noted above, I think. For most revolvers, a cartridge that is shorter by the margin you are talking about it perfectly fine. Rifles are a different story; some are very finicky about feeding depending on COAL, others much less so. That's been trial and error for me.

 

[38SPL HV]

I also prefer to use the crimping groove. Lyman uses a similar weight 125 gr cast bullet in 38 Special using 5.2 grs W231 (same as HP38), 1.440” oal…+P pressure 18,300 psi.

Your load should be good to go in your 357 Magnum.

 

[stansdds]

For revolvers, crimping the case mouth into the bullet's crimping groove takes priority over COL.

 

[AlHunt]

I'd also advocate for using the crimp groove. I haven't looked at the published data, but assuming you're in the ballpark of safe, you could always back the load off a bit and work it back up.

The comments seem to suggest you're comfortably in the "safe" ballpark. Probably even enjoying a hotdog and beer.

 

[gwpercle]

For revolvers ... the crimp groove is where you seat the bullet .
Book OAL's are not written in stone ... adjust OAL as needed ...
at one time OAL wasn't even listed in reloading manuals ... Look at the 1970 Speer manual ... no OAL's
In the Lyman cast Bullet Handbook #4 they show ...
38 Special = Lee 358-125-RF with a max load of 4.8 grs - HP38
@ 896 fps - standard pressure load .

5.0 grs HP38 in a 357 mag. case will probly give you 900 fps and be just into +P 38 Special performance ... a very safe / soft load shot in a 357 Magnum revolver .
Good Luck and Load Safe,
Gary

 

[71vette]

As others have stated, load to the crimp groove. 5 grains of HP-38/Win 231 is a very mild 357 load with a 125 grain slug. You’ll be extremely safe. Proceed and have fun!