Cast bullet velocity limits?

[Larry Gibson]

Thanks, Larry. So, is that independent of caliber then? Another question, hows does boolit length effect the threshold?

Larger caliber bullets fair a bit better becase a given defect is generally a much smaller % of the mass and and if a surface defect, most often what is created during acceleration. The surface defect is also farther from the center of spin. Additionally large calibers have slower twists and many times their max velocity is below the RPM threshold range.

The longer and pointier a cast bullet nose is, especially if unsupported, the lower the RPM threshold will be.

Larry Gibson

[303Guy]

Thanks. I understand the unsupported nose concept, it's the fully supported long round nose boolit I am asking about as those would seem to be subject to a lot of yaw if unbalance at the rear or nose but then the yaw may be dampened by the distance from the base or nose - see why I don't understand? Also, the long boolit may have a smaller stability factor. But, one often hears of a longer boolit being more accurate in a particular gun than a shorter one but that would be due to throat alignment mainly.

[TooTallDean]

TWO YEAR BUMP.


That is a lot of info to digest. And well worth doing so!
Someone from another forum (CanadianGunNuz.com) pointed me to this thread.
I have done some casting in the past for a muzzle loader rifle and a C&B revolver, but I am new to casting for Centre-fire rifles.

I notice this thread does not go into Powder Coated boolits at all, probably due to no new posts in the last two years.
So, has there been any testing to see if PC affects the Max RPM?

I would like to cast for a Lee-Enfield and an M-1 Garand. Both are 1-10".
For the L-E, I can go with a heavy boolit to make up for the low velocity, or use a lighter load like 16gr of #2400
http://castboolits.gunloads.com/show...Rifles-Article

But the Garand gas system needs to stay within a set range. I dont think that 16gr would cycle a Garand?
Also, it was noted before that a slower powder is easier on a cast lead boolit. However, a slower powder is NOT recommended for the Garand gas system, as it creates too high a port pressure. This can damage parts. H4895 or IMR4895 is best.

So, how to build an accurate, reliable functioning load for the M-1? Hard cast WW, PC'ed and water quenched? Or try PP?

Thanks!

[Jupiter7]

TWO YEAR BUMP.


That is a lot of info to digest. And well worth doing so!
Someone from another forum (CanadianGunNuz.com) pointed me to this thread.
I have done some casting in the past for a muzzle loader rifle and a C&B revolver, but I am new to casting for Centre-fire rifles.

I notice this thread does not go into Powder Coated boolits at all, probably due to no new posts in the last two years.
So, has there been any testing to see if PC affects the Max RPM?

I would like to cast for a Lee-Enfield and an M-1 Garand. Both are 1-10".
For the L-E, I can go with a heavy boolit to make up for the low velocity, or use a lighter load like 16gr of #2400
http://castboolits.gunloads.com/show...Rifles-Article

But the Garand gas system needs to stay within a set range. I dont think that 16gr would cycle a Garand?
Also, it was noted before that a slower powder is easier on a cast lead boolit. However, a slower powder is NOT recommended for the Garand gas system, as it creates too high a port pressure. This can damage parts. H4895 or IMR4895 is best.

So, how to build an accurate, reliable functioning load for the M-1? Hard cast WW, PC'ed and water quenched? Or try PP?

Thanks!

Well as you may know, PC is still in its infancy. 2yrs ago, nobody was dry tumbling or spraying. Piglet method was cutting edge technology and Hi Tek coating was only available from Bayou and not really any using it. I highly suggest you visit the "Coatings & Alternatives" sub-forum here. Some of us have varying degrees of success. I've personally shot 1" 100yd groups at 2K FPS with PC in the 30-30. I've pushed .223 past 2200fps recently and it's promising. Others have done more. I don't use anything other than PC now.

[303Guy]

The Lee Enfield seems to lend itself to paper patching. That said, I am looking at a plain cast boolit for one of my Lee Enfield's.

I haven't really looked into powder coating but it sounds like a lot of effort for small batches but worthwhile for large batches. That's just a perception which maybe wrong. If wrong I might look into it sometime.

I'm a fan of the heavy boolit to make up for lower velocity concept. I've shot 265 gr boolits but they are a tad long for magazine use. They work well on turkeys! Or were those 245 gr? Whatever they were, they had full penetration and left a big hole! They were actually intended for pigs but to make them more versatile I gave them a wide and shallow hollow nose for small fame. The theory being that the thin rim of the hollow nose would open up on small critters while leaving the boolit as a flat nose with penetration for pigs. I ended up with 194 gr boolits