Fire Lapp 9mm Carbine

[BSJI]

I searched around for recommend loads for fire lapping a 9mm carbine with a 16" barrel. Didn't find any!

So I came up with my own...

I used pure lead unsized bullets from a Lee 356-120-TC. The bullets were rolled between two steel plates to impregnate them with LBT lapping compound.

Cases were once fired and unsized. CCI 500 primer. Powder used was 0.3 cc of Trail Boss thrown with a Lee dipper.

I finger seated the bullets in the case and then carefully chambered the round.

When fired the bullet easily exited the barrel, but the bolt barely moved. I had to manually cycle the action to eject the case. Only made a mild, pop too.

Worked for me. Four shots seemed to smooth the bore nicely.

[Catshooter]

Very nice BSJI. I did a Kel-Tec carbine years ago and the groups shrank to one quarter of their previous size. Very worthwhile.

I used, if I recall correctly two grains of Clays under a Lee tumble lube 115 boolit. The load was too light and would only exit the barrel about three out of four shots. Pain in the patootie.

Welcome to the forum.


Cat

[Big Boomer]

Catshooter: That is the reason Veral Smith cautioned in his book to do "trial" loads for getting the lap-impregnated boolit out the end of the barrel. While doing my fire lapping, I first loaded up one round to see if it would do just that, exit the barrel. Then loaded up as many as I thought necessary. One note, stainless steel barrels require significantly more rounds than ordinance steel, or so I found. YMMV. Big Boomer

[RobS]

I would use a little harder boolit though. Pure lead has a tendency to hit the throat and expand more leaving a larger than desired throat area. Try something in the neighborhood of 10-11 BHN or so and size the boolit to the diameter of the bore. The lapping compound will enlarge the diameter of the boolit but will swage back down when you seat it in the case.

[spfd1903]

Veral's instructions for fire lapping suggest a BHN of between 10 and 14.

[RobS]

Veral's instructions for fire lapping suggest a BHN of between 10 and 14.

and there you go

[BSJI]

With a tight patch, the bore felt nice and smooth.

Slugging, post lapping, was much less balky too. The slug measured .357, by the way.

I'm happy with the results...

[dubber123]

Glad you are happy with the results. I've always used air cooled WW's, which falls right in line with Verals recommendation. I wish I could get a way with 4 shots. 50 seems about average for the revolvers I have been doing. :)