Cast vs. Jacket/Plated Velocity and Loading Question

[TurkeyHuntsman]

Group:

I'm perplexed - can anyone help? This discussion pertains to .45 ACP loading.

I've loaded 4.5 grains of WST in Berry's 230 gr RN to use as a reference load. They consistently shoot ~750 fps from my Rock Island full-size 1911, and this velocity is very close to what's predicted in most of the loading data that I've seen.

I acquired 4 different cast boolits to try out, 2 copies of the 200 grain H+G SWC (one is LEE, the other an unknown mold, perhaps Magma), some NOE 453-196 SWC, and some Lyman #452374, 225 gr RN. All four boolits shot very accurately, BTW - and the NOE was truly incredible, putting one ragged hole in at 7 yards.

I loaded 4.7grs WST in the 3 different SWCs, and 4.4 grs WST in the Lyman RN. The chrono results were quite a surprise!

First off, the Lyman chrono'd at 830 fps with just 4.4 WST! This is considerably faster than the 750 fps of my Berry's 230 gr RN "reference" that has 0.1 gr more charge. In addition, Lymans handbook shows a range of 4.2 - 4.7 WST with a velocity range of 707 - 794 fps. Why is it that my mid-range load of 4.4 grs is providing a velocity well in excess of Lyman's maximum published velocity of 794 fps with 4.7 grains? And yes, the OAL was set to Lyman's standard in the handbook.

My over the max velocity would suggest an over-pressure condition, but my load charge is just mid-range! Is there that much of a discrepancy in cast boolit velocities from the published data vs. actual? And, are cast boolits generally much faster than their plated or jacketed counterparts? Again, the Berry's 230 RN is 750 fps, while the 225 gr Lyman is up at 830 fps...significantly faster.

So far as the SWC's - the two H+G copies chrono'd at 850 and the NOE at 870 fps average. That is pretty fast, I'd guess this is +P veocity, but then again these are just 200 grain, and in general should fly faster than the common 230 grain RN "ball ammo" that is rated at 850 fps.

So, I'm trying to sort this all out. To summarize:

1) Will cast boolits of the same shape and weight shoot faster than plated or jacketed with the same powder charge?

2) Are there huge discrepencies between published cast bullet velocities, and actual results...perhaps moreso than for jacketed/plated bullets?

3) When I load and chrono them...should I keep my charges so that they are always under the max. published velocities for that particular boolit?

I appreciate some expert advice on this, I want to keep it safe. Thanks in advance!

-Dennis
San Diego

[Yodogsandman]

1) yes, cast boolits are slipperier and have less drag than plated or jacketed. With equal loads, lead boolits will have less pressure than jacketed, too.

2) too many variables with cast boolits to accurately predict the speeds as chrono'd by someone else with their load. Seating depth, your scales, cartridge expansion, barrel length vs test barrel length, barrel/chamber conditions are some variations.

3) you should start with START loads listed and carefully work up towards MAXIMUM loads with caution. I like to cross reference loads from multiple trusted sources, if possible. Load books can be wrong, too!

[OS OK]

I dunnoh really. I've scratched my head on this one before, listened to many ideas of 'why this or that' on J's VS cast. I think that I'm believing more in the fact that cast seals the bore better than J's do, keep more pressure behind them and generate more velocity.
There is only so much horsepower so to speak in a specific grain load...if you let some slip by due to poor obturation, well...less horsepower left to push the boolit.
I look at the jackets and plated material on boolits that were dug out of the berm and see black carbon fouling all around the circumference and along with the rifling marks...in my little peanut, that is gas getting by the round on it's way out the door.
I look at slow motion videos of rounds exiting the muzzle and see a tremendous amount of fire coming out ahead of and with the boolit. I am even more convinced.

[TurkeyHuntsman]

Thanks for your inputs, guys. Again, since there are so many variables that affect my measured velocity vs. what the books say, should I simply adjust my powder charge so that I'm never exceeding the max velocity as shown in the load books - regardless of what charge I actually end up with?

[OS OK]

Dunnoh for sure...work it up for best grouping, paying close attention to primer condition and over expanded webs, I think if you stop short of a true sharp edged primer, that in a quality case, web expansion wouldn't be a concern as in a very high pressure rifle round. As far as FPS measure it last and take what you get. My loads tend to outrun the books a bit...25-50 FPS or so in the 1911 but for the loads in my .308 i'm about 125- 150 FPS ahead of the books in my long range load. Tight chambers, the leade etc. all play a part and are different from one weapon to the next.
I can see you have those gears turning on this one.

[runfiverun]

well.
if you load a cast boolit and a jacketed bullet with the same load the lead one will be faster.
it's slipperier and engraves the rifling easier.
the other thing that happens quite often is the base of the cast boolit will occupy more of the case volume available which can raise pressures in many cases.
what this means is quite often a jacketed start load in the book is more like a halfway load with many cast boolits.

to answer your question.
you need to decide if the extra fps is from the lead boolit or the fact it's taking up more room in the case.
or if it's a little bit of both, and where that puts you on the pressure scale.

[TurkeyHuntsman]

Is 850 - 870 fps an abnormally high velocity for a 200 gr SWC in a 1911? The MIL-issue 230 gr FMJ ball ammo is spec'd at 850 I believe.

[JSnover]

Is 850 - 870 fps an abnormally high velocity for a 200 gr SWC in a 1911? The MIL-issue 230 gr FMJ ball ammo is spec'd at 850 I believe.
I have load data from at half a dozen sources that say you can do it. It's near the top end but not over max. What mold and what powder are you using?

[TurkeyHuntsman]

I have load data from at half a dozen sources that say you can do it. It's near the top end but not over max. What mold and what powder are you using?

I'm glad to know I was not way over the top! The mold and powder data is in my original post above.

[JSnover]

I'm glad to know I was not way over the top! The mold and powder data is in my original post above.
My Lyman 48 list 804 fps as a max for 4.7 WST under their 452460 which is pretty near a clone of your NOE 452-200 (Lyman base band is a little taller than the two driving bands) but their test barrel was a universal receiver, for what that's worth.
L48 shows 452630 (200gr BBSWC with one lube groove/two bands, looks identical to the H&G) over a max charge of 4.9 WST @ 840fps. If your chrono shows 850-870 and all is well I'd call that good enough and personally wouldn't feel a need to go faster.
You're happy, the gun is happy, the brass is happy, nuthin' wrong with that.

[TurkeyHuntsman]

My Lyman 48 list 804 fps as a max for 4.7 WST under their 452460 which is pretty near a clone of your NOE 452-200 (Lyman base band is a little taller than the two driving bands) but their test barrel was a universal receiver, for what that's worth. (snip)

Jsnover, I made a mistake in my original post, which I corrected. The NOE was actually a 453-196 "button boolit" / HG 130 clone at 196 grains. This explains why it was a bit faster than the two HG 68 200 grain clones that shot to almost identical velocity.

That HG 130 clone was wicked accurate in my gun, and it just looks damn cool as well. I'd like to get an H+G 130 clone mold somewhere. Is NOE the only firm that currently makes them?

[runfiverun]

saeco might be still doing their 130 which is quite similar.

[Geezer in NH]

Thanks for your inputs, guys. Again, since there are so many variables that affect my measured velocity vs. what the books say, should I simply adjust my powder charge so that I'm never exceeding the max velocity as shown in the load books - regardless of what charge I actually end up with?NO never exceed the powder maximum grains. Velocity don't COUNT

[TurkeyHuntsman]

NO never exceed the powder maximum grains. Velocity don't COUNT

Makes sense, and I never exceed the max chage weight listed. But what's going on if I am loaded far below the max. charge weight, and yet I'm getting measured velocities that are far above the maximum velocity shown in the load data? Does that indicate a problem...or not?

[JSnover]

Makes sense, and I never exceed the max chage weight listed. But what's going on if I am loaded far below the max. charge weight, and yet I'm getting measured velocities that are far above the maximum velocity shown in the load data? Does that indicate a problem...or not?

The figures vary from manual to manual, that same load in another book might be listed as near max. Just watch for signs of pressure as you work your way up, double check your components, weights and dimensions. If it gets a little scary, you're probably going as fast as you need to. No point in tempting fate.

[TXGunNut]

The 45ACP isn't designed to go fast. Best loads are generally just above what's required to cycle the action.

[n55bz]

Which powder is WST?

[JSnover]

Which powder is WST?
Here it is, from Winchester:
http://www.wwpowder.com/shotgun.html