RCBS 45-255 rnfp leading

[tomme boy]

I am trying to figure out this boolit. I have tried it fast and slow in my handi rifle. It leads the first 3" of the bore.

The bore measures 0.4525" and I am sizing the boolit to 0.454". The lube has been NRA 50/50. The lead is 50/50 range lead and WW's with 2% tin added. Water dropped.

I have tried a bunch of other designs and none do this unless I run them too fast. Anyone have any opinions?

[tomme boy]

Anyone?

One thing this boolit has a very small lube grove. Ant the base is really thick as to other boolits I have used.

I also use a 300 gr boolit from accurate molds an have no leading with this boolit no matter how I load it. I size it to 0.454" just like the 255gr one and the same lube.

[Wayne Smith]

The bore measures .4525" or the groove measures .4525"? If it is truly the bore, there's your problem.

[tomme boy]

0.4470" x 0.4525" This is what it measures

[Iron Mike Golf]

Boolit seated too deep? Lots of free bore? I don't have that model rifle.

[tomme boy]

I'm seating and crimping it at the crimp grove so I don't know if that would be it or not.

[Larry Gibson]

Depending on the "range lead" there might be too high an antimony content for that design of bullet with the minimal lube groove.

Try; WW + 2 % tin alone. Then try the range lead +2% tin + 50% lead. Don't WQ either one, let them AC for 10+ days.

What load BTW?

Larry Gibson

[tomme boy]

I have been using 7.3 gr of red dot for most of them. Then 18gr of 2400 an 12gr of Unique for the faster ones. I tried some imr 4227 but that powder just does not burn at all.

[tomme boy]

The range lead seems to average about 3/4 old cast bullets and the rest is jacketed. It seems fairly hard as is.

[Larry Gibson]

The range lead seems to average about 3/4 old cast bullets and the rest is jacketed. It seems fairly hard as is.

The "old cast bullets" if commercial cast are probably "hard" with a high % of antimony. The lead from amny jacketed cores also has antimony in it. That is the way most "range lead" is unless it comes off an indoor range where a large % of .22LR is shot. I suggest the addition of lead and tin as previously mentioned. I add 4 lbs of lead and 6 1/2 oz tin to 15 1/2 lbs of m the bunch of range lead that I have. It make a much better alloy that way. You can easily adjust the amount of lead +/- for the range lead you have.

If you continue to get leading and really want to use that bullet then the bearing surface is brobably a bit much for the emaller lube groove. You might lube the bullets as usual with the 50/50 and then tumble lube with LLA as per the instructions.

Larry Gibson

[runfiverun]

try cutting the tin in the alloy.
adding a coat of the lla could help.
but where you are getting the leading suggests the boolit isn't gripping the rifling.[load related]
you might need to look at that area of the bbl too it could be rough as all get out.

[tomme boy]

Its not rough. I have used a few other boolits an the only one that does this is this RCBS one. Thats what does not make any sence to me.

What do you think would happen if I cleaned the bore really well an then swabing the bore with moly?

[runfiverun]

i use moly in some of my boolit lubes.
moly is fine but it has a tendency to allow moisture under it.
if i didn't live in a low humidity area i wouldn't use it.
i'd give something else a try like the tumble lube a shot.
a coat of cooked off jpw,with some mineral spirits to help them dry.
or just rubbing a bit on the exposed part of the boolit before chambering.
you could also try a batch of water dropped or straight ww alloy.
it could just be something about the boolit/throat shape like the nose scuffing off.
not quite a bore rider not quite groove depth..