.40 S&W bullet set back?

[Josh45]

Hello, I have a question regarding some .40 I am trying to make.
I am thinking it could be the dies, Cases or the gun itself.

the dies are Lee Carbide .40 S&W. My question to this is, When I resize my case what should I expect my case mouth to be and how big should the die mouth be?

I am trying to eliminate as many possible issues to get to the main reason the .40 I am making keep getting bullet set back in the gun I am loading for.

Next, The cases I am loading is Federal and R-P. I am using the Federal at the moment and after resizing, There case mouth is at .419.

As for the gun, It is a Taurus PT-940. I removed the barrel and checked the with the plunk test. There flush and drop in and out with out any help needed.
But when I let the slide run home, It tends to move the bullet back from 1.125 down to 1.123, Then I try again to make sure it isn't a fluke and I can end up getting 1.119 with the same rechambered round.

I don't even have to flare my cases to get the bullet into the cases. I skipped flaring and went to seating and the case showed no resistance. Just sat right in with very few with some light resistance at the start and then none after.

The bullets are 180 Gr FP. I tried the same thing with a 165 Gr FP and a 165 Gr HP. All of them did the same thing. Using R-P case for the HP and another Federal case to test the 165 Gr.

The only thing I can come conclusion to is, The resizing die is not doing giving me adequate neck tension to hold the bullet in place.

The throat on the gun is short, Or the cases are just no good at all.
Measured some of the bullets and some came out at .399 - .400.
There from a site called "EverGlades"

Any help would be appreciated

 

[JO JO]

R-P Brass is known to be thin walled in 40 s&w I had bad set bad with Hornady XTP and
R-P brass. You can search the web and find many others that has had trouble with R-P and
40 s&w. I use it in 9mm no issues at all,so for me I avoid R&P and 40 s&w others have no
issues at all. Be safe as they say measure twice cut once.

 

[Striker Fired]

It sounds a lot like the die is oversize, the r-p brass being what it is maybe makes it worse, but I've used both r-p and half of my .40 brass is Federal(both old and the new junk)and I have no neck tension issues. So that leaves only the sizer die not resizing small enough, since you stated it did it with two different bullets.

 

[JLDickmon]

Take your mic and check the ID of the sizing die.. Like Striker said, sounds oversized.

 

[LiveLife]

The cases I am loading is Federal and R-P. I am using the Federal at the moment and after resizing, There case mouth is at .419.

The only thing I can come conclusion to is, The resizing die is not doing giving me adequate neck tension to hold the bullet in place.

Your resized cases should measure less than .418-.419" outside of case mouth and depending on the thickness of the case wall, measure around .395" inside of the case mouth.

Using Lee carbide sizing die, I just full-length resized and measured several headstamp cases and I got the following (note that outside/inside measurements may vary depending on the "rounded/oval-ness" of the case mouth post resizing - Yeah, they don't always come out a perfect circle ):

Headstamp - Outside diameter - Case wall thickness - Inside diameter:

Winchester: .418-.419" - .012" - .394-.396"

PMC: .418-.419" - .012" - .393-.395"

R-P #1: .418-.419" - .010"-.012" (1/3 of case was .010") - .397-.399" (Uh oh ... )

I measured a second R-P case.

R-P #2: .418-.419" - .010-.011" - .397-.399" (Oh no! )

Federal: .418-.419" - .010-.012" - .396-.397"

Since all the cases resized to .418-.419", perhaps the thinner case walls of R-P and Federal cases may be causing the larger inside diameter and resulting in decreased neck tension.

If you have a Lee FCD, you could try using it on the case neck to see if it reduces the case neck further than your resizing die.

If you can't reduce the case neck with your sizing die/FCD and still experiencing bullet set back, I would recycle the cases.

 

[Josh45]

Okay, I just checked it and if I did it right, I am getting .423 - .427.
That sounds way off to me? Most of the time I will get .424.
I tried a few more times and it would show me .411-.414. But I rechecked it and I kept getting .424

I did check it with the decapping pin left in. If that makes a real difference?

BDS,

Thanks for that! I appreciate the info and I did use the FCD and have some set to .421 and .420.
The bullet set back is less of a problem but now it just reduces nothing which is good or up .0005
Goes from 1.125 to 1.124.5

 

[LiveLife]

What bullet type are you using?

With larger than jacketed (.400") diameter bullets sized .401", using the FCD may post size the bullet and reduce neck tension (brass case wall springs back out but squished bullet don't). I meant to use the FCD to further resize the case neck down - not to use after seating/crimping the bullet.

Could you load some test rounds without the FCD and see if the neck tension is better?

 

[Josh45]

Okay, Sorry I forgot to mention if it was OD or ID.
I just redid another case and this was the spec before sizing.

Before Sizing O.D - .424 - .426 ( Out of round came to .419 as well

Before Sizing I.D - .402

After Sizing O.D - .419 ( Checked at .418 in some areas )

After Sizing I.D - .397

BDS,

There FMJ-FP from a company called Everglades. I used 180 Gr and also 165 Gr FMJ-FP.
I did use some without the FCD and those caused more setback IIRC.
The data I put up here is sizing one case of Federal.

 

[Otto]

But when I let the slide run home, It tends to move the bullet back from 1.125 down to 1.123, Then I try again to make sure it isn't a fluke and I can end up getting 1.119 with the same rechambered round.

Everytime the bullet hits the feed ramp the bullet is going to setback a bit...this happens with factory ammo as well.
You should measure the case/bullet tension by pressing the completed round on a bathroom scale, you'll want at least 40 lbs of pressure on the bullet before it begins to move further in the case.

 

[Josh45]

Otto,
Your right but for it to keep going shorter and shorter each time bothered me because I have not had this kind of issue with other calibers or brass.

I decided to test one piece of each headstamp and what I got is that Blazer Brass and Winchester brass I.D was at .393 and the O.D at .417-.418

R-P measured I.D at .397 and so did a Speer case.

 

[LiveLife]

Otto, I think the OP was about the bullet set back issue with thinner walled R-P and Federal cases.

I just made several dummy rounds using Winchester and Federal cases with 40S&W 180 gr TCFP/RN Montana Gold jacketed, Berry's/Rainier plated and Missouri lead bullets (I used .420" taper crimp for MG/Berry's/Rainier bullets and .422" taper crimp for MBC bullets).

I used G22 with a new OEM captured recoil spring assembly and fed the dummy rounds from the magazine with the slide locked back.


Results:

Montana Gold jacketed bullets:
Winchester case did not produce bullet setback even after second feeding/chambering.

Federal case produced .002" reduction. Second feeding/chambering produced total of .004" bullet setback.

R-P case produced .0005" reduction. Second feeding/chambering produced total of .001" bullet setback.


Berry's/Rainier plated bullets:
Winchester/Federal/R-P cases did not produce bullet setback even after second feeding/chambering.


Missouri lead bullets:
Winchester/Federal/R-P cases did not produce bullet setback even after second feeding/chambering.

 

[LiveLife]

Josh, I just tested a Blazer case with Montana Gold bullet with no setback, even after the second feeding/chambering from the magazine.

If you are experiencing bullet setback with jacketed diameter bullets, you could always try Berry's plated bullets (they are sized slightly larger than jacketed bullets) with Federal/R-P cases or use different headstamp cases.

 

[Walkalong]

An expander that is too big can cause problems as well. Check it.

 

[LiveLife]

Very good point. I flared the test cases just enough so I could set the bullets on the case mouths without the bullets tipping over.

 

[popper]

The expander die should set the neck tension. The sizer die should shrink the case to where the expander can do it's work. Figure any case wall < .009 is too thin and trash it. Get a die that sizes .419 or LESS (.400 + 2*.010). I think all my expanders are .397. You can use the Lee die for cast or proper sized bullets. Those bullets are too small.

 

[LiveLife]

The neck tension is set by the resizing die and as posted by Walkalong, "could" be removed by the expander.

Here's Lee's powder pour-through expander die insert showing how much of the expander I use (blue arrow).

 

[gamestalker]

Resize 5 or 10 of each type brass, and then put a nice taper chamfer on the inside of the mouth to allow for easy seating, then seat the bullet. Do not bell the mouth or employ a crimp. This will tell you if it's the die, too much bell, or a crimping issue.
I hear this a lot and have so far been on the money. I'll bet you you'll find you can't move those bullets by hand against the bench, or with recoil effect.

BTW, I stopped belling the case mouth on any of my cases some 20-25 yrs. ago and haven't have any problems what so ever. However, if your loading non jacketed bullets you may have to be careful to avoid shaving the bullet.

GS

 

[GLOOB]

Since you're not using the flaring die, I'm pretty sure we can rule that out. And since your sized case dimensions seem to be within spec, your sizing die is probably not the culprit. And since your bullets are measuring 0.399-0.400, hmmm. Wait, that doesn't sound right! I'd say it's a combination of thin brass and small bullets.

I'd pay particular attention when seating, and set aside the rare cartridges that seat with the least resistance. When you're done with your batch, take those cartridges and press the nose of the bullet against your bench. If they shorten by more than a couple thous, I'd be worried. If they pass, move on. Chamber them 4 times. Why 4? I dunno. Why not 4? If they are still in an OAL range you're comfortable with shooting, then the rest of your batch is probably ok. Some brass is just too thin! Unless you want to order an undersize sizing die, you just have to junk some brass. I have had to junk some R-P 38 brass and some W-W 45ACP brass.

Also, don't overcrimp your ammo! Crimp just enough to remove any leftover flare. Overcrimping can reduce neck tension.

If for some reason you're using sizing lube, be careful not to get any on the inside of the case. Also, brushing the inside of the case with a brush dipped in acetone might increase your neck tension a tad by removing soot and tumbling residue. I have never done it; it's just a theory!

Whenever I'm flaring my 45ACP cases, I have two bins. I set aside those that don't offer much resistance into a separate bin. That's the quickest way to sort out my R-P and S&B cases. The flaring die hardly touches them. They still work fine for jacketed, but I try to reserve them for my cast loads. That might be of use to you if you get some thicker cases in your mix of brass and you have to start flaring.

 

[Striker Fired]

Yep, as Gloob just said, I use all my newer Federal brass(most of it is small primer) for cast bullets, I only have about 100 r-p and thats just sitting in the corner.

 

[GLOOB]

Hah, If we were neighbors, I'd trade you. I have just a handful or two of the newer small pocket Fed sitting in the corner, and I have a lot of R-P.

 

[zeke]

You can minmize setback with a lee undersize die and reduced diam expander. Problem is then seating bullets straight, a comp seating die helps. Set back is more evident with the lighter jacketed bullets. Even factory rounds can be prone to setback .001-.002.

Learned the .40 setback with Rem brass the hard way. After mag blew out bottom of HP .40, which has a unusually heavy recoil spring.

 

[Josh45]

Thanks everyone for the help.
I did try to press them in by hand but they would not budge.
I didn't try the bench as I had left after my last post in this thread. Being that they wouldn't move by hand, I decided to go ahead and try them. Setting them at 1.125-1.127, They all chambered and I got to shoot them with pretty good results from the loads and the gun.

I will keep this brass to the side for lead rounds from now on when I get a mold for the .40 and use better brass. I will also make sure to measure all the bullets I tend to use to make sure they are within spec of each other. Even the OAL of the bullets are all over the place.

Some went from .595 to .545. Not acceptable by any means really. I'm going to keep checking the resizing die to make sure it isn't the cause. Thanks