Lyman 401638 OAL

[Ed_Shot]

Recently started loading .40 S&W with Lee 401-175-TC using Lyman CB 4th Ed. data for Lyman 401638. The boolits look identical....can someone give me the OAL of the Lyman boolit?

[prs]

I do not have a manual at this location, but with the Lee boolit you mention, I find the most harmonious result to be had setting the length so that the case margin meets the junction of the truncated cone and side wall of the boolit or "jest a hair" longer. If you use these in one particular barrel, use that barrel as a gague to verify that fit. Maybe someone will come along with the printed manual data soon.

prs

[Ed_Shot]

Thanks. Lyman calls for an OAL of 1.100 with their #401638. I've been loading the LEE 401-175-TC at OAL 1.115. My LEE 401-175-TC boolit OAL is .595. I was just wondering what the boolit OAL is for Lyman 401638 for comparison of seating depth.

[williamwaco]

OAL should be determined by testing feeding and functioning. Not by looking it up in a manual.

Your cartridge should be the maximum length that will feed reliably through your magazine and chamber and cycle reliably without the bullet touching the rifling. If it touches the rifling, sooner or later a fatter than normal bullet will prevent the slide from closing. It is a fundamental law of nature that this will happen at the worst possible time.

This length can and often does vary from one handgun to the next even with the same bullet.

There are three conditions you must meet.

1) It must be short enough to fit in the magazine.
2) It must be short enough that the front band of the bullet does not inhibit the closing of the slide.
( This is the purpose for using the barrel as a Gauge. )

3) It must feed reliably from the magazine into the chamber and allow the slide to lock into battery. It must do this when you work the slide manually, AND when the firearm is fired.

To test this issue, make three or four dummy cartridges with no powder or primer. Deliberately seat the bullet out too far. Then gradually turn the seating stem in about one turn, reseat the bullets a little deeper, and test for all three conditions, by loading them into the magazine and manually cycling them through the action. Repeat until everything works manually. When everything works reliably, stop. Seating the bullet deeper will only raise pressure and eventually it will be too short to feed reliably.

Now load about a dozen and check them at the range.

DO NOT LOAD 100 rounds and then find out later that they will not work.




See:

http://reloadingtips.com/pages/loading-40-sw.htm
for my experience with the .40

[Ed_Shot]

Thanks, I get prefect function, good accuracy, and no signs of excess pressure with Lee 401-175-TC loaded at COAL 1.115 using loads listed for Lyman 401638 in the Lyman 4th Ed. I went though a detailed dummy cartridge process before I settled on a COAL of 1.115 for my pistol.

Lyman 4th Ed does not list loads for 401-175-TC but it does list loads for Lyman 401638. Both boolits are nominal 175 gr. and have similar profile. My 401-175-TC bullet has an OAL of .565 as cast. My question is: What is the overall length of Lyman's 401638 bullet as cast? Just because I'd like to know the variation in the two bullets.

[williamwaco]

My question is: What is the overall length of Lyman's 401638 bullet as cast? Just because I'd like to know the variation in the two bullets.



Who has one of these molds ?

.

[Ed_Shot]

Thanks all, the answer is the boolit OAL for Lyman 401638 is .570 which is .005 longer than the Lee 401-175-TC.

[rensan4]

I bent my small primer sleeve and cant get intouch with Lyman,anyone have any ideas.my local gun shop doest carry any.

[noylj]

+1 Williamwaco
The COL is dependent on:
1) bullet ogive, where "looks similar" is not good enough
2) when the magazine lips release the round
3) feed ramp geometry
4) chamber dimensions.
All of these change. Even cast bullets from the same mold will have small variations in the ogive and meplat. There is NO COL that is optimum for ALL guns.
You need to determine the COL range that works best in your gun and then the COL that is most accurate.
My 175gn TC bullets are loaded from 1.176 to 1.211" (EAA Elite and two Para 16/40s). This range may be different than what your gun will feed and chamber.