Fire lapping load for the Sw 500 mag .

[Joe C]

Not sure if this the right place to post this or not but thought I would ask anyway .

Anybody have a fire lap load for the 500 SW ?

I have been doing searches on this forum and a google search and can't find anything.

I was thinking of trying Trailboss powder . in the Hodgdon manual 8 gr with a 370 gr cast gives 750 fps
thought I would try dropping it a grain or two and chronoing a few .

I also talked to a Hodgdon tech and he warned me about going too low with the trailboss , said the pressure drops off pretty quick and you could end up sticking a bullet in the barrel .

I have other powders , bullseye, red dot , 231 etc but don't have any kind of starting point for them, at least the trailboss load gives me a place to start.

thanks

Joe

[Tatume]

Trailboss is probably a bad choice. It works best at or near 100% loading density.

My experience with fire lapping is to use a minimum charge of Bullseye, just enough to get the bullet out of the barrel. Be prepared to remove a stuck bullet or two. It's easy to do. You need a brass rod and a heavy hammer. Light taps with a heavy hammer are infinitely better than sharp raps with a light hammer.

Only load one at a time and tip the muzzle up before each shot. You could start with 8.0 grains, and it will probably exit the muzzle fine. You're looking for the minimum reliable speed.

[birddog]

Veral recommended the fastest powder available. Just enough to push bullet out of barrel is all that is needed. When I lapped my SRH 480 I could watch the bullet lob up about 150' and start to fall back down. The Ruger needed 140 rds to clean everything up. S&W should not be as bad.
Charlie

[C. Latch]

I used 700-x and Green Dot when I firelapped my .45.

What all do you have on hand in the fast-burning range?

[Motor]

The Lyman cast boolit manual list loads using Unique. I've been shooting 12gr of Unique with a Lee 255gr REAL boolit (yes a ML boolit) sized down to .501 and lubed with A-Lox. The freekin thing is unreal accurate at 50 yards often cuttin holes. I have not measured the velocity but I'm fairly sure its sub-sonic.

[Joe C]

First off , I want to thank all for the replies .

I decided to try the Trailboss powder since the hodgdon manual showed a load that had the lowest velocity of any other data I could find, and I had no clue where to start with powders like bullseye, red dot , etc.

It had a load of 8 grs for 750fps out of a 10" bbl .

I am shooting a 5" gun so just the 5" less barrel would drop it a bit .

I loaded up 3 each of 7 gr , 6 gr , and 5 gr.

I shot them over the chrono .

I don't remember the numbers exactly but I think the 7 gr was in the hi 500 fps range
the 6 gr load in the low 500 fps range , and the 5 gr load I used , ( I remember those numbers) was in the
450 - 500 fps range .

I wanted to chrono the fire lap loads , but it was getting kind of dark and the chrono wouldn't read them ,but they felt a little hotter .
Probably because of the increased resistance of the lapping bullets.

thanks again for the suggestions

Joe

[44man]

I don't know why to fire lap a S&W. Super good barrels as they are. But Bullseye has been the powder to just get a boolit to exit. You can see the boolit go if right. No need for speed. I doubt a lapping load will get to 200 fps. Even if a boolit falls out the muzzle, it is enough.

[kenyerian]

Always used bullseye.

[jrayborn]

What is the reason to have the boolit at such a low speed? No argument either for or against the practice, just curious.

[dubber123]

Keeping the speed low on a relatively soft lead boolit helps prevent any skidding when going up the bore. You want the lapping slug to follow the lands/grooves as closely as possible. You also are basically shooting unlubed boolits, and it doesn't take much speed to start leading a bore.

[jrayborn]

Thanks!

[44man]

The reason to not use too soft too. Veral suggests around air cooled WW lead so it will not skid.

[dubber123]

The reason to not use too soft too. Veral suggests around air cooled WW lead so it will not skid.

Air cooled WW's is all I have ever used, and it has always worked perfectly for me.