Cast Bullet Lube on Targets

[Shed]

Hey Guys,

I have a question about lube coming off cast bullets. I'm currently reloading .45 Colt with Unique powder & SNS cast bullets that have the blue lube strips at the bottom of the bullet. I make my target loads so they chrono out of my 5.5" SAA clone at around 865-880 fps at the muzzle. I've noticed that at the start of shooting I get good accuracy out of them, but by the time I get to 40-50 shots groups are opening up and the number of fliers increase. By this point, the gun has usually heated up considerably, to where I can feel heat on the top strap of the frame. it is usually at this point that I will notice pieces of the blue lube strips on the target as well.

My question is, does the heat from the barrel and cylander cause these lube strips to melt and/or shear off and create tumbling, either in the barrel or in flight? Aside from letting the barrel cool off, do you have any recommendations for preventing this?

As always, thanks for your time and insight.

-Shed

 

[Blue68f100]

I've shot 100-200 rounds at a time using MBC 45acp SWC (blue lube) and never noticed any difference. Never see any indication of lube on the target. If your seeing it on the target then it's leaving a trail or coming off during flight. I don't see how this would effect accuracy once the bullet has left the bore.

 

[Hunter86004]

by the time I get to 40-50 shots groups are opening up and the number of fliers increase

When your gun cools down, does your accuracy return to normal? Do you notice any fouling in the barrel?

Some bullet lubes behave a bit strangely at temps that are a bit high.

 

[Shed]

I've shot 100-200 rounds at a time using MBC 45acp SWC (blue lube) and never noticed any difference. Never see any indication of lube on the target. If your seeing it on the target then it's leaving a trail or coming off during flight. I don't see how this would effect accuracy once the bullet has left the bore.

Do you think run-out may contribute to this?

 

[Shed]

When your gun cools down, does your accuracy return to normal? Do you notice any fouling in the barrel?

Some bullet lubes behave a bit strangely at temps that are a bit high.

I usually only put 50-70 cartridges through the gun at any given range session without a cool down period. I can give it a try. In general, when I start the session with a cool barrel the accuracy is always good.

The gun is a Uberti Cattleman II btw.

 

[243winxb]

Lubes have different melting temperatures from 125 to over 200 degrees F. Rotation of bullets in flight may spin any remaining lube off. I have dug bullets out of the berm with blue or red lube in the lube grooves.

does the heat from the barrel and cylander cause these lube strips to melt

i think no. Powder burning, yes.

Try larger diameter bullets.

 

[Hunter86004]

In general, when I start the session with a cool barrel the accuracy is always good.

Sounds like if you want to continue using the same bullet and load, you're going to need a cooling period or live with the accuracy problem.

 

[frankmako]

Could be leading the barrel and/or gun is getting too hot.

 

[Blue68f100]

Do you think run-out may contribute to this?

I have no idea. I have enough magazines that I shoot 50 rounds before I stop to reload. No cool down, except for the time to load up all my mags using a speed loader. I have a Kart match barrel in my 1911, hard fit. After 200 rounds there is no loading. I use WST as my powder, BE velocities. I use a custom seating stem that only contacts the shoulder of the SWC. Are you getting any leading? If you allow the gun to cool down does the accuracy comes back?

 

[243winxb]

http://www.snscasting.com/45-long-colt/
If shooting the 180 gr, maybe try a different bullet with a longer bearing surface like the 250 gr. May get better alignment from throat to forcing cone.

Bullet diameter should be at least .452" or bigger to fit the groove diameter of your barrel.

"Runout" the bullets need to be seated straight into the case. M die expander.

Watch for post sizing of the loaded rounds bullets.

 

[FROGO207]

You should be able to see the keyholeing if the bullet is tumbling. My thoughts are: your accuracy problems are the bullet is either too small or the throats are too small for the barrel and you are getting leading and this decreases accuracy as the lead builds up. This could also cause keyholes in the target. If the bullet lube is soft enough then it might rub off as the bullet goes through the target but I have never had this happen to me yet. I have bullets that are sized for the gun and throats that allow the bullet to fit the barrel and can shoot several hundred rounds with a revolver with good accuracy. You should be able to do this as well when everything is set up correctly. I would slug the barrel and all the cylinders to see what you have and report back. Then we can have a better idea of how to help.

 

[Shed]

A friend thinks the cylinder throats are smaller than the bore diameter, and suggested the following resources:

http://www.castbullet.com/misc/accrsa.htm

http://www.gunblast.com/Brownells_Reamer.htm