Lee 358-125RF in a 9mm ?

[Swede 45]

Well, I´have a mold (lee 358-125RF) that i cannot get to shoot in my revolvers.. (actually, i have other designs that shoots way better..)

So, i´m thinking about trying that one out in my 9mm.. I have shot alot of commercial casted 124gr lead through that gun previously so why not?

Now..
I made up a dummy round and made a plunk test, both in my barrel and a go-no go gauge, no problem with fit.
Seated the Lee boolit up to the crimpgrove, just so it dissapeared under the case edge. (no, not crimped into the grove, just a normal 9mm taper..)
Came out at 26.3mm/1.035 inch col.

I sized the boolit to .357 (smallest die I have..) and measured it with my micrometer.. showed 9.06mm
(Sorry I´m in the metric part of the world!:-|) to my converter app, thats about .35669 inch?
I pushed one boolit through the barrel and measured it.. came out at 9.02mm (.35511 inch)

I did the same thing with a leftover commercial boolit of previous stock, and got 9.07mm/.35708 inch "raw" and 9.02mm/.35511 out of the barrel.

Then I took a look at both boolits and realized that my casted boolit had longer riflingmarks/longer surface than the commercial one!
112137
My boolit has about 30% more contact to the rifling.. up to the crimp grove/"step" they are about the same, but the commercial one has a "step" that ends the surface section..

How much problem is that extra surface on my Lee going to cause in pressure ?
Anyone here using this boolit in 9mm?

The commercial cast ones at the right, was usually loaded with 4.9grains of Vihtavouri n-340, seated to the "step" (Can´t recall the col).

Would backing down to 4.5gr as start be good to go? Or is that extra surface going to mess things up for me?
(Vihtavouri says min 4.7- max 5.1gr with a 124gr lswc at 1.1442 col)

Oh, by the way, my barrel is poly rifled!

Anything else that I have missed or should think of?

Swede

[dubber123]

I see no problems whatsoever. I doubt the extra bearing surface will matter much as far as raising pressures significantly. What I would look for, is how much case volume both your existing proven safe load, and your new load take up. If seating depth in the case with the new boolit is similar or LESS, pressures will be very similar. If the new boolit seats deeper, you will need to reduce your start charge and work up as usual. Have fun and good luck.

[tazman]

What dubber said is correct.
I have used that specific bullet in my 9mm with good success. Since your barrel measures .355 the diameter you are sizing the cast bullet should be perfect.
If your chamber will accept it you could even go to .358. The larger diameter and bearing surface will not cause increased pressure by itself. The extra bearing surface may actually improve the accuracy.
As dubber said, the only real concern here is how much bullet is inside the case. If the Lee bullet is substantially further inside the case you will need to rework the load.
I didn't need to for my pistol but I don't push maximum loads either. I seem to get my best accuracy at just above starting loads.

[Swede 45]

My Lee boolit seats about 1mm / 0.039inch deeper..

[Scharfschuetze]

With that large diameter nose, you may have issues with the boolit chambering if loaded to the normal overall length of the 9mm, depending on how your 9mm is throated.

If you have to seat it deeper, you will loose some case volume in order for it to chamber. If so, I'd start on the low end with your powder charge as that loss of volume added to the 30% more bearing surface may be something you want to plan for in developing your starting load.

[Swede 45]

I made up a few dummies to test cycling.. they fed and chambered just nicely in any possible way I tried.. I inspected the dummies for signs of touching the rifling, setback by feeding and damage from feeding.. nope, nothing!
I usually keep my normal col for jacketed at about 29mm and some.. and this one comes at 26.3 when seated to just cover the crimpgrove.
I just tried that col, based on the esthetics by hiding that groove..:-P
And I will for sure start low.. the 4.5gr is .2 below the recomended start for a normal 9mm cast lswc (probably of similar design as the bullet shown?!) , and I think I´ll even start bit lower..
Velocity is not the goal here..

[dubber123]

I shoot the BRP 360640 which is similar in profile the the LEE 125 RF you show, but heavier at 150 grains. I too seat to just cover the crimp groove, and my OAL comes in at 1.078" I just started low and worked my load up accordingly. It works and shoots very well.

[FergusonTO35]

Nothing wrong with that boolit in 9mm but I wouldn't seat it that short. I would go with 1.055 or so. Really would like to see Lee come out with this same design with a slightly longe ogive and no crimp groove.

[MtGun44]

If it feeds and chambers in the throat, it should be fine. Either or both could be
problematic in many guns.

Bill

[Thumbcocker]

Shoot that boolitin a Glcok 19 2 BHP's and a convertible Ruger sized .358 in all of them. Seated to where the crimp groove is just covered. All of them dote on it. Start low and work up to get good functioning. Very versitile boolit. Medium burning rate powders have worked best for me.

[c1skout]

I don't have any 9's, but my 38super, 357mag, and 38special all like that boolit. I leave the crimp groove exposed for the super and shoot it at around 1200fps. Works great.

[Swede 45]

Been to the range for a quick test..
4.2, 4.5 and a 4.9 charge of n- 340.
All loads worked fine without any signs of high pressure..
Accuracy similar between all loads, about 2inch at 25 meters. Same poi for them all..
Recoil ranged from soft to snappier.. The 4.9 charge showed a bit of leading in my poly barrel.
Aircooled coww alloy, white label 50/50lube..

I'm going to continue experiment with this boolit in another alloy , watercooled and my new Tac lube..
I also have another barrel with a quick traditional rifling to try out.. Will also try them sized to .358

This gun is superaccurate with j-bullets and it would be fun to get the same accuracy with these boolits!