I just ran across this when looking up a load for a 155gr jacketed flat point in 40S&W using AA#2.

Sierra 150grJHP min 4.7 (900fps) max 5.5 (1050fps)
Nosler 150grJHP min 5.4 (1022fps) max 6.4 (1118fps)
Speer 155grJHP min 5.8 (840fps) max 6.5 (956fps)

Accurate Arms free manual lists:
Nosler 150grJHP min 6.3 (1063fps) max 7.0 (1155fps)

Can I deduce from this that for a jacketed 150/155 gr bullet, the safe limits for AA#2 is 4.7 to 7.0 with an approx. velocity range of 840 to 1118fps? All these loads were supposedly worked up in a 4" barrel. I find it odd that the load info with the same powder and similar weight/style bullets can vary so much between sources.

Ruger#1

you find this more often than not in your reloading manuals. Thus it helps to have several of them and kinda take an overview of where to start and where to finish. As a rule, I let my bullet dictate which manual I am going to use as a REFERENCE.
If you had all the detes for the different loads you would probably find that some of the components were different. As some of the companys can't even agree as to what diameter is best for a .308 bullet, you can't expect them to agree on any of the other facets of the game. So what the data is saying is: using the components listed, under the conditions at the time, and shooting them thru the pistol they used, they got the following results and you should be able to closely replicate the results if you used the exact same components...if they'll let you borrow their pistol.
As each weapon is a law unto itself, you need to think of the reloading data as more of a guideline than an absolute. This is why each of them tell you to approach maximum with caution.

What is safe in a 40 S&W depends a great deal on the chamber support.

If I put a case in the barrel and scribe the outline of the feed ramp on the brass with a needle, I can then measure the feed ramp intrusion into the chamber.

When I did that with my stock Glock 22 40 S&W barrel, I measured .235" intrusion.
Yet when I cross section 40 S&W brass, the web is only .180" thick.
That leaves .055" of thin unsupported case wall. That may be just barely ok with 35,000psi, but When I tested overloads with the stock barrel, the cases get a smiley faced embossment 90 degrees from the extractor mark at 25%, 32%, and 36% powder in excess of Alliant's and Vitavouri's published maximum loads for 40 S&W and Power Pistol and 3N37. This is the feed ramp case bulge warning that is very close to a horrible experience.

However when I TIG welded up the feed ramp and re cut the feed ramp and chamber to have case support at the case web, I can then overload 68% extra powder beyond the published Alliant maximum. The 68%+ safety margin is more in keeping with what I have measured for 9mm pistols.



[ 03-29-2003, 22:13: Message edited by: Clark ]

I decided to take a middlish value (6.0), load 10 or so and watch for pressure signs. What are good indicators of over-pressure other than primer cratering/flattening? This is a Glock 23 and I'm just plinkin/paper punching so all I am looking for is reliable function.

Thanks,
Ruger#1

All guns, just like people and dogs, are INDIVIDUAS!! No two can be expected to perform the same!! What you see is just more proof of this unavoidable fact!!

I'd probably start with the lowest listed load(4.7?).Might be easier to end up with a couple of rounds that wont cycle your gun ,40 Glocks and the kaboom thing,ya know? Primer flattening works for me, but only within the same brand and kind of of primer. Cheapo chrono can give you some insight into what sorta power your ammo's making.I mean if that 155 Flat Point is coming out of your barrel at 1500fps you might be a little over Some of the powder companies seem to get way more velocity out of a given recipe than I do.

Just got back from the range... 6.0gr is too much, got some cratering but no flattening and a couple had faint smileys where the ramp isn't supporting the brass. Gonna make up another 10 with 5.0 and see how they shoot. Unfortunately, it's a 90 minute drive to the range... it'll have to be a next weekend thing.

Ruger#1