Varying OAL with 40 S&W

[01SVTvert]

Finally started reloading 40 S&W on my LnL with a set of Lee dies. I used these dies before in a single stage and had no problems.

I am running pulled 155gr bullets and most have small marks along the curved surface where (I assume) a puller grabbed them. I initially set up my OAL at 1.130 and after a few tests seemed to be there. I then checked my first 50 or so and found a wide variance in OAL. Most were at 1.131 but about every 5th or 6th I would get 1.136+ No rhyme or reason to the length change, sometimes its one in ten, other times it two in six.
I ended up culling about 15 in the 100 I just ran then then put them through the size and crimp die again and they all consistently ended up at about 1.126 to 1.128....... Great...

One, I would not buy these pulls again as they all have minor damage. Two, I tried being really consistient on the downstroke of the handle to bottom out the press and with the amount of force to eliminate me being the variable.

Observation: the seating knob on the die is loose, like the threads do not perfectly match and the head has some "wobble" dont know if that is normal. Also, I am able to crimp the case back to a width minus 1 thousandth from max for a 40 S&W case so I know at least the crimping protion of the die works well and consistently.

Any input? Thinking I need to buy some standard 155gr heads and eliminate the projectiles as the problem, then maybe swap to Hornady dies. Problem I am having is that I loaded up 500 180 gr rounds before this on the single stage with these dies and had absolutely no problem keeping the OAL within 1 thousandth or so.

 

[greencobra]

I have seen the same with my .40s. I have my overall depth set for 1.133. What I've always assumed but have no real proof, is I have the bullet canted in the case when I run it up so I see a discrepancy in OAL after seating. As routine, when loading 40s on my single stage, I run it up a second time and it is at my set depth. For those of you wondering, the seat plug is free of lube or misc debris that would retard the bullet seating. I use a 175 gr SWC w/BB normally, but now, because it was all I could get last week, it's a 180 gr flat nose. Because of the headspace issue, I don't bell the case mouth out very much, just a bit for the bevel based bullet to sit down and not tumble off during the upstroke. I have the roll crimp die ever so slightly touching the case mouth just to get back the mouth shape really. The bullet has enough body surface so I don't have to break out the taper crimp die. I do take the barrel out of the gun and drop a few loaded rounds in to check my headspace.

You know, I don't think using reclaimed bullets will hurt you any if you're not loading for super accuracy, say just for paper punching and practice. But if the marks are in the way of the seat plug of course it will impede seating and explain why you have depth problems. I use a hammer/impact style puller so I'm not familiar with the puller marks you describe.

 

[greencobra]

I was hoping Eddie C would wonder by, I'd bet he could help get this monkey off our backs.

 

[powerman]

see my thread "308 Overall Length issue, not consistent bullet seating" see post #9,
the lee bullet seat swivels a little. so if bullet goes in a little cocked it may change the lenght a little when it moves to center when the bullet gets seated.
You can't however lift up a little to let it center on the progressive press.

if your loading cast bullets, some time the excess lube gets stuck to the bullet seater, but when that happens then they end up short.

 

[01SVTvert]

No cast bullets in these dies, ever. I am being pretty particular about how I place the bullet but it looks like it is time for a different set of dies...

 

[Gammon]

No cast bullets in these dies, ever. I am being pretty particular about how I place the bullet but it looks like it is time for a different set of dies...

All reloading machines have a certain amount of flex. Progressives have the most flex. The reason for the difference in OAL could be as simple as a really tough case in the sizing station that prevents the machine from fully cycling, which would result in an increase in OAL at the seating station. As long as the difference was minor I wouldn't worry about it.

 

[DukeInFlorida]

With a light, or whatever you need to use to see in there.... Take a look inside your bullet seating die.
Most likely, you will notice that the part of the die that pushes the bullet into place has a hollow TAPERED cavity.
Which means that the bullet seater isn't pushing against the end of the bullet, where you are measuring.
It's more likely pushing against the sides of the bullet. Where the curve of the bullet is.
That bullet curvature is what is varying. The variation in the curvature is sometimes greater in cheaper bullets, and lesser in better quality bullets.
Hollow points tend to vary more than other styles.

1) The variation that you are seeing in assembled length is OK. Do NOT start trying to play games with .40 S&W. They tend to be very sensitive to pressure, as a function of seated depth. Use the length that the book gives you, and keep a chart of the measurements. Do a simple average (total of all the lengths added up, divided by the number of measurements) and a bell curve chart (write down each measurement, and see how many overs are matched by unders.) If you are coming out with an average and a top of the bell curve number that is where the book recommends, don't worry about it.
2) You can either have the manufacturer of the seating tool make you a new insert which pushes on the end of the bullet during seating, or you can make one yourself (presuming the machining ability).

I had to make a custom bullet pushing insert for several of my set ups due to similar issues with hollow points in cast lead bullets.

 

[wacky_doug]

Do NOT start trying to play games with .40 S&W. They tend to be very sensitive to pressure, as a function of seated depth.

Is .40 S&W also especially sensitive to the amount of crimp, i.e more crimp = high pressure? I've been trying really hard not to over-crimp, but I've noticed that the velocity of my loads are lower that the velocity stated in the reloading manual. Maybe by 50 fps. That may not seem like much, but the range on the load with this powder is 961 to 1047.

OAL is fine for me, so I'm wondering if the crimp is affecting this, or if perhaps it's just a reflection of the barrel length used to make the measurement in the reloading manual vs. my gun.

 

[01SVTvert]

The stated minimum OAL for the load I am using is 1.125 I am trying to keep the OAL at 1.130 I am, at best, always over minimum. I am also loading on the low end of the load as all I am looking for is consistent function with the lowest load in a G35.

 

[IDPA Mike]

Finally started reloading 40 S&W on my LnL with a set of Lee dies. I used these dies before in a single stage and had no problems.

I am running pulled 155gr bullets and most have small marks along the curved surface where (I assume) a puller grabbed them. I initially set up my OAL at 1.130 and after a few tests seemed to be there. I then checked my first 50 or so and found a wide variance in OAL. Most were at 1.131 but about every 5th or 6th I would get 1.136+ No rhyme or reason to the length change, sometimes its one in ten, other times it two in six.
I ended up culling about 15 in the 100 I just ran then then put them through the size and crimp die again and they all consistently ended up at about 1.126 to 1.128....... Great...

One, I would not buy these pulls again as they all have minor damage. Two, I tried being really consistient on the downstroke of the handle to bottom out the press and with the amount of force to eliminate me being the variable.

Observation: the seating knob on the die is loose, like the threads do not perfectly match and the head has some "wobble" dont know if that is normal. Also, I am able to crimp the case back to a width minus 1 thousandth from max for a 40 S&W case so I know at least the crimping protion of the die works well and consistently.

Any input? Thinking I need to buy some standard 155gr heads and eliminate the projectiles as the problem, then maybe swap to Hornady dies. Problem I am having is that I loaded up 500 180 gr rounds before this on the single stage with these dies and had absolutely no problem keeping the OAL within 1 thousandth or so.

I just checked a factory box of Blazer 40 S&W, there was a variation of
5-8 Hundred ,thousandths of an inch.
Then i checked a box of .380. The tolerance was much closer.
2-4 Hundred,thousandths of an inch.
I would not sweat it. I get variations of bullet ,case and overall weight and length. Not much, but I drove myself crazy trying to be perfect. If they feed and fire properly, thats fine by me. With my ability, factory match ammo, or my hand loads, will work the same for me, only cheaper.
Thanks, Mike

 

[DukeInFlorida]

No, once the pressure in the case starts pushing, the crimp will give way, and the bullet will be moving down the barrel. A tight enough crimp is needed, however, to hold onto the bullet just long enough for the powder to get burned properly. Too loose, and you have burning powder rolling down the barrel, wasted gas pressure. The only downside to over crimping is the danger of cutting through the jacket, especially on plated bullets. And, I still maintain (in spite of many discussions on the subject) that really over crimping can cause sizing issues with the bullet itself. Especially with cast bullets. But it won't really affect the pressures. OAL is the big concern when it comes to pressures.

Is .40 S&W also especially sensitive to the amount of crimp, i.e more crimp = high pressure? I've been trying really hard not to over-crimp, but I've noticed that the velocity of my loads are lower that the velocity stated in the reloading manual. Maybe by 50 fps. That may not seem like much, but the range on the load with this powder is 961 to 1047.

OAL is fine for me, so I'm wondering if the crimp is affecting this, or if perhaps it's just a reflection of the barrel length used to make the measurement in the reloading manual vs. my gun.

 

[Rob Boudrie]

Do NOT start trying to play games with .40 S&W. They tend to be very sensitive to pressure, as a function of seated depth.

This is particularly true if loaded with Clays powder. Some people like it because it can be very soft shooting for a given velocity, but it can be very sensitive to overcharge.

 

[wacky_doug]

No, once the pressure in the case starts pushing, the crimp will give way, and the bullet will be moving down the barrel. A tight enough crimp is needed, however, to hold onto the bullet just long enough for the powder to get burned properly. Too loose, and you have burning powder rolling down the barrel, wasted gas pressure.

I've done the "spiral target test" or whatever you call it, and I didn't see evidence of powder burning down the barrel. So I think I've got my crimp right. Thanks for the info.