Running handguns slugs WAY past their intended velocity

[Sevens]

Up for discussion and opinion--
This was part of a response I got from Coy Getman, CCI/Speer Sr. Technical Coordinator thru e-mail. This was more than two years ago. I was looking for load data using the .32 Auto's typical 71 grain FMJ slug -- in .327 Federal Magnum.

In many calibers you can use “the bullets that fit” the 327 Fed is not that caliber if you intend to use full-power loads. You’ll tear the forcing-cone up or stretch the frame with bullets not designed for full-pressure loads in the 327 Fed. Understand that is not an idle warning, it will happen, this is the place for premium bullets when top velocities are desired.

The way for me to “stay an expert” is to provide tested data and change that when components change. If we tested someone else’s bullets and they changed them and we did not know it, you’d be looking for gun parts and calling me “something other than an expert”.

Since getting that e-mail, I've loaded many hundreds of these light little pills, but I've NEVER loaded them to any harsh velocities -- I've typically loaded them around 1,300 FPS and I once loaded them to 1,590 FPS, all chrono'd. The 1,590 FPS loads were launched from a 5.5" Ruger Blackhawk.

It's likely possible to really ramp these light bullets up to crazy velocities in .327 Federal without exceeding maximum pressures, but his warning about damage to forcing cone and possible frame stretch have simply kept me from running them even as fast as I run the proper Hornady XTP slugs.

I've seen occasional load data (typically from a magazine article) where they ran 60 grain Gold Dots (also meant for .32 Auto) and the 71 grain pills at faster speeds.

I'm curious if anyone has any opinion or further explanation of how/why a bullet that was likely designed for speed around or under 1,000 FPS and for a much lighter pressure cartridge can/may damage a handgun when run at much faster speeds and much harsher velocities.

FWIW, I have no good reason to run these bullets any faster than 1,300 FPS. I have no end-game here, I'm just having fun with them and learning as I go.

I'm familiar with the concept of finding a properly constructed bullet--I load the Hornady XTP-Mag bullet in .460 S&W rather than their run of the mill .45 Colt slug for the same reasons.

I'd just like to know more about it and hear some ideas.

[Brian Pfleuger]

I can't add much except to say that a Hornady rep gave me a similar warning about shooting their 90gr .308 handgun bullets in a .30-06. He didn't say it would damage anything, just that I would effectively have bird shot rather than a bullet.

[PA-Joe]

If you have noticed, Hornady now makes XTP-Mag pistol bullets for use in rifles. These have heavier jackets for the higher velocities.

[buck460XVR]

Speer and Hornady both have warnings about using bullets intended for .45 Colt velocities with the .460 S&W Mag. Both claim the thin jackets can lead to bullet separation and excessive forcing cone/top strap erosion when used at .460 pressures and velocities. I figure they know what they're talkin' about.

[FrankenMauser]

I can't help you Sevens. But, I did want to add...
After getting a similar warning from Sierra, I was hesitant to load any more of the 71 gr FMJs or 60 gr XTPs in hot loads. But, loading them in wimpy loads just didn't seem right. So, they sat, and sat.

I got tired of staring at the box of 60 gr XTPs on my shelf, and loaded them in .30-30 on top of a max load of Trail Boss, last week. The results should be... interesting.

[Jim Watson]

I have no experience in the .30-.32 range but can say that it is possible to blow .357 revolver bullets out of a .35 Remington rifle at amazing speeds with decent plinking accuracy.

[zplinker]

How about 110 gr. Sierra Blitz bullets into a 35 Rem., chrono'd at 2950. They actually shot well, but were explosive on cottontail rabbits.

[Sevens]

I figure they know what they're talkin' about.

I concur, but was hopin' for a but more than that.

[steveno]

using real light bullets was part of the problem (along with using the wrong powders in reloading) with the 357 max in revolvers. 110 and 125 grain bullets were too light. 140 grain bullets were marginal. 158 grain bullets were really the lightest that should be used.

[Sevens]

It seems to me that the light weight of these bullets isn't the real problem -- it's much more the short length of them (due to the light weight!) That's what tears up .357 Magnums when excessive 110 and 125 grain loads are put through them. That's likely what killed the .357 Max.

How about a L-O-N-G jacketed slug in .312" that weighs only about 50 grains?! That'd be cool, and frightfully fast!

[jimbob86]

My guess is the design and materials used (jacket thickness, particularly at the base, and lead alloy of core) are not tough enough for the acceleration and rotational forces involved.... when you whack a bullet designed for 15K PSI with 3-4 times that, and spin it way faster than it was designed to be spun, it might not act like it was designed to act.... if the base got deformed at all, it may not want to go down the tube as quickly as it is supposed to, raising pressures..... just my guess.

[Brian Pfleuger]

Originally Posted by Sevens

How about a L-O-N-G jacketed slug in .312" that weighs only about 50 grains?! That'd be cool, and frightfully fast!

Well get on it, man!

All you'd need to do is machine smaller titanium cores and bond a copper jacket to them. That should be really light. If you did it right, you should be able to make a bullet that is the same length as a standard bullet but weighs just barely 1/2 as much.

Maybe you could make one that's the dimensions of a standard 150gr .308 bullet but weighs 85 or 90gr. That would be sweet.

[SHR970]

At least where 71 gr. FMJ bullets are concerned I am skeptical of the answer. In the attached photo, the three bullets on the left were fired through a mid 60's Detroit steel station wagon tailgate (2 or 3 layers of steel depending on where it hit) and were found in the Mojave Desert rock sand mix behind it. The most deformed one hit a substantial rock after penetrating the tailgate. The right most bullet was fired into wet newspaper for a penetration test. The three left bullets are Winchester, the right most is Fiocchi 71 gr. FMJ 32 ACP.s.
I have a hard time believing that the launch would be violent enough to distort the bullet enough to cause forcing cone damage. If we were talking about a 60 gr. HP that has a thinner jacket I would be more inclined to agree.

[SL1]

Not an expert on this. But, I have read that the problem with pushing bullets over-pressure IN A REVOLVER is that they will "rivit" in the forcing cone. That is, when the bullet hits the cone with too much pressure behind it, it expands radially to fill the cone, then needs to be swaged back down to fit into the bore. That delays the bullet's travel and increases the pressure in the case. It should also increase the stress on the forcing cone.

Unfortunately, I can't seem to find where I read that.

SL1

[SHR970]

Three of the bullets pictured demonstrate the concept of riveting based on rapid violent deceleration while encountering stiff resistance.