9mm won't seat in Sig P938

[Laminarman]

I'm relatively new here and have reloaded .45 successfully. I am now using RCBS carbide dies to load 9mm 125gr Penn RNBB lead bullets using WSF (I have a bunch of that around..like 15 pounds, and 1,000 of those bullets) I posted here a long time ago about COAL and was cautious about making the cartridge too short as there is a lack of data for the WSF. Factory RN hardball ammo Fiocchi 9mm measures 1.156 while the sources I look at recommend 1.169 COAL (I assume that's the maximum?) Anyways, I've got her down to 1.135 and it still won't pass the "plunk" test in the barrel (nor will it in my STI Guardian.) Sure I can go shorter to pass the "plunk" test, as I'm assuming the very round nose of the bullet is preventing the seating, but how do I know that? I can make up new dummy rounds but if I get real short to get seated will I blow off a limb even at the lowest starting measure of 4.0 g of powder? Any help is appreciated and I'm sorry for my lack of experience, I simply don't know anyone who reloads.

[Virginia John]

I think you need to keep trying to figure out the proper OAL for your weapon by continuing to make dummies reducing the OAL .01" at a time until it "plunks". I think you will find that you may be down around 1.10" or even a little shorter. You may also want to look at the crimp.

[Bohica793]

Are you certain that it is the bullet profile causing the issue or is your case possibly bulged due to a bullet that is too large in diameter? Have you tried running the round through a Lee Taper Crimp die to insure that the round is properly sized? Just a couple of thoughts.

[Ed_Shot]

What is the length of the 9MM Penn RNBB 125 gr boolit?

[Laminarman]

Thank you for the replies everyone. The Penn bullet measures .5665 in length. The factory round, loaded, at it's widest at the top portion of the casing is .3755 while the Penn loaded is .3760. It does not appear bulged. I tried to taper crimp it more but it looks like it was a bit "over done" on my dummy round. I can sure go shorter but I was just afraid of building too much pressure. Does COAL mean maximum or minimum length? Being new, I thought that length was "the length" and you can't vary from that. Guess not, huh?

[freebullet]

Your light on details for anyone to offer much meaningful help.

Here's how I figure out how long the round can be without making a zillion dummy rounds. First with the slide closed stick a dowel down the barrel till it rests on the breech face and mark it at the end of the barrel. Now open the slide insert a boolit and put something behind it to hold it there. I use a toothpick broken and wedged gently in place. Now put the dowel back in and mark it at the end of the barrel. Now measure from the outside to the inside of the marks. For lee 1r boolits make your dummy round .020" less than your measurement, and for lee 2r I start the dummy rounds .015" longer than the dowel measurement. This works like a champ and takes the guess work out of how long it should be for your gun and that boolit.

What ever length the gun wants is what will work. Now you'll need to figure out the charge data end of the equation. Post results from the above test, what your sizing the boolits at, and the book length for the data your using for further assistance.

The 938 is not known for having a bad throat and I've found that it will function with the longest rounds that will feed in a full size xd. Those same rounds are to long for many budget 9mm's and won't feed, but the 938 cramps them in the throat 100% and shoots them accurate.

[Laminarman]

Your light on details for anyone to offer much meaningful help.

Here's how I figure out how long the round can be without making a zillion dummy rounds. First with the slide closed stick a dowel down the barrel till it rests on the breech face and mark it at the end of the barrel. Now open the slide insert a boolit and put something behind it to hold it there. I use a toothpick broken and wedged gently in place. Now put the dowel back in and mark it at the end of the barrel. Now measure from the outside to the inside of the marks. For lee 1r boolits make your dummy round .020" less than your measurement, and for lee 2r I start the dummy rounds .015" longer than the dowel measurement. This works like a champ and takes the guess work out of how long it should be for your gun and that boolit.

What ever length the gun wants is what will work. Now you'll need to figure out the charge data end of the equation. Post results from the above test, what your sizing the boolits at, and the book length for the data your using for further assistance.

The 938 is not known for having a bad throat and I've found that it will function with the longest rounds that will feed in a full size xd. Those same rounds are to long for many budget 9mm's and won't feed, but the 938 cramps them in the throat 100% and shoots them accurate.

Thank you Freebullet. I have no idea if Penn uses a Lee 1r or Lee 2r mold but I would bet it's the 2r as the Lee site shows that to be the only 125gr bullet. Now, are there other molds besides Lee's?? I'll try to find that and get back with more info.

[tazman]

If you can detect where the curvature of the bullet nose begins, use that point as the spot to put even with the case mouth when you seat the bullet regardless of OAL.That should get it to pass the plunk test.
Hodgdons data site shows 4.7 grains as max with a 125 grain cast bullet and shows 4.0 as a starting charge. If you begin with the starting charge or slightly less powder, you shouldn't have any pressure problems unless you push the bullet waaay too deep into the case. With WSf, even the max load is listed well below the max pressure the cartridge is designed for.

[Laminarman]

Thank you Tazman. I did notice that the case mouth does not flare quite enough to accept the bullet easily but they seat straight. Nothing I do with the sizing/decapping die changes that. Once in a while a little lead will get spilled over or the gas check lube, but the case measures the same as the factory load. The bullet is quite a bit more rounded than the factory hardball ammo. It's getting late now I'll try again tomorrow with a fresh head.

[tazman]

I just went to the Penn bullet site and looked at the picture. You won't be able to leave any of the flat side of the bullet exposed beyond the mouth of the case if the throat on your gun is the least bit tight.
Try to load so the case mouth is even with the start of the curvature. That should get them feeding. Start with the start weight of powder and work up from there until you are satisfied with the accuracy and function of the gun.

[Ford SD]

I'm relatively new here and have reloaded .45 successfully. I am now using RCBS carbide dies to load 9mm 125gr Penn RNBB lead bullets using WSF (I have a bunch of that around..like 15 pounds, and 1,000 of those bullets) I posted here a long time ago about COAL and was cautious about making the cartridge too short as there is a lack of data for the WSF. Factory RN hardball ammo Fiocchi 9mm measures 1.156 while the sources I look at recommend 1.169 COAL (I assume that's the maximum?) Anyways, I've got her down to 1.135 and it still won't pass the "plunk" test in the barrel (nor will it in my STI Guardian.) Sure I can go shorter to pass the "plunk" test, as I'm assuming the very round nose of the bullet is preventing the seating, but how do I know that? I can make up new dummy rounds but if I get real short to get seated will I blow off a limb even at the lowest starting measure of 4.0 g of powder? Any help is appreciated and I'm sorry for my lack of experience, I simply don't know anyone who reloads.

Not sure if this helps (working on a 1911 9mm clone)

I am loading the lee 124g bullet --the length of the bullet only is .555
loaded length that passes the plonk test is 1.047 for my gun.
the flat sized portion of the bullet is just a hair above the case mouth when loaded

I also did a plonk test with my length in a friends S&W and it was a good length in his gun

I have shot air cooled, loaded with 4.0 /4.1 / 4.2 / 4.3 g of WSF they were either under sized or too soft and leaded the barrel .356 dia
primers were not showing any pressure signs max plublished is 4.7g 124g lead roundnose (win book)

I have another 100 loaded
water dropped and at 358 dia and have no worries
just waiting for a nice day and a day off work to be at the same time
it was snowing today

[freebullet]

My most accurate reliable 9mm rounds don't pass a plunk test. It's pretty common for cast to perform the best with the boolit lined up and seated in the throat just like rifles. That's not possible with fat boolits as I described above.

From Tazman's description of your mold it's a 1r. He is correct, it won't feed with the sidewall of the boolit out of the case. If you do the 5min test I mentioned and follow the seating depth for 1r I'd bet it will work.

For better performance I'd recommend the Mp molds 359-125hp. It works the best in the p938 for me. When seated .020" in the throat it has no equal. The mp359-125 no groove molds are splendid in the 938 and the lee 356-125 2r is a good performer too.

[Wayne Smith]

As to other molds look at the Accurate website. Tom will get you a mold much faster than Miha unless he happens to have the one you need in stock as an overrun.

[DougGuy]

OP it sure sounds like your barrel need to be throated. If you push one of your boolits into the chamber and tap it to seat it in the throat, then measure back to the barrel hood. Record this measurement, then compare it with one of your loaded rounds. You may find out that the base of the boolit has to be pushed farther down in the case than you want it to be. This is common happens all the time. Your barrel needs to be reamed so the throat is .0005" greater than your boolit diameter, so the boolit will go into the throat. It also needs to be deep enough so that the boolit will chamber when seated and crimped at your chosen COA. Send me a PM if you are interested in having this done.

Seating deeper in the case, -especially- in a high pressure cartridge such as 9mm can be dangerous, and what this does is create a second problem, as a workaround to the first problem, the throat being too tight or too short or a little of both.

Edit: This is a reply I made in another thread for a pistol with a different problem, but the photos here show what needs to be done to get your loaded ammo to seat and plunk and function correctly at the COA you want. The barrel on the left in the photo had a long enough throat from the factory, but it was only .4015" in diameter and would not permit a boolit sized .402" to chamber and fire. After reaming, the throat has .150" worth of .4025" freebore in front of the chamber mouth, and the .402" boolits seat without issue. This was a 10mm barrel that needed throating, but the same exact principle applies to the 9mm.

http://castboolits.gunloads.com/showthread.php?273575-Throat-tighter-than-rest-of-barrel-on-Walther-PPQ&p=3199963&viewfull=1#post3199963

[Laminarman]

Thank you for your help folks. I spent a bit more time with it tonight. I crimped slightly tighter and the plunk test seems to pass at about 1.099" Doing Freebullets test with the dowel, I measured 1.105" and making it .020" less makes it 1.085" but since I'm new to this I'm not sure if that's really "close" or not to 1.099" These are small numbers. I have yet to load powder but want to know if it's dangerous starting at 4.0 g WSF at 1.099+/- or not. Also, and this is a really stupid question, how does one know if the mold is an R1 or R2 or whatever??? Is Penn using a proprietary mold or Lee mold? Thank you once again.

[tazman]

That Penn bullet doesn't resemble any of the Lee molds for 9mm. It is a 1r design. With the 2r designs the nose is longer and not nearly so blunt.
You should be fine with 4.0 grains of WSF to start.
You may start showing pressure sings before you get all the way to max at 4.7. Look for flattened primers where the edge of the primer is no longer rounded. Also look for blown/pierced primers where the dent from the firing pin is blown out. If you are not showing any of these you are probably fine. It would be good if you could verify your velocity with a chronograph. If you are reaching max speeds, you are probably reaching max pressure as well.
WSF is a good powder to start with in this cartridge. The pressures are a bit lower than with other powders until you get to the heavy weight bullets.

[Laminarman]

That Penn bullet doesn't resemble any of the Lee molds for 9mm. It is a 1r design. With the 2r designs the nose is longer and not nearly so blunt.
You should be fine with 4.0 grains of WSF to start.
You may start showing pressure sings before you get all the way to max at 4.7. Look for flattened primers where the edge of the primer is no longer rounded. Also look for blown/pierced primers where the dent from the firing pin is blown out. If you are not showing any of these you are probably fine. It would be good if you could verify your velocity with a chronograph. If you are reaching max speeds, you are probably reaching max pressure as well.
WSF is a good powder to start with in this cartridge. The pressures are a bit lower than with other powders until you get to the heavy weight bullets.

Thank you Tazman. I had been thinking of investing the modest cost in a chronographer and you might have just convinced me to do that.

[freebullet]

Since you mentioned tightening the crimp I'll mention that you should pull a boolit from your dummy round and measure it to make sure your not sizing down the boolits. It's cheap insurance against leading.

Cycle your dummy rounds through the gun by hand and let the slide close full speed. Does it cycle them perfectly at 1.099, how about 1.085? I'd seat them at 1.085 (my guess is it wont feed dummies longer than 1.090) and start at 3.6 working up in .2gr increments. Getting a slender nose profile mold will increase performance and capabilities. Let us know how it works out.

[mongoose33]

Sometimes the bullet is seated too long, but more often in my case it's a lack of sufficient taper crimp. The 9mm case is tapered, i.e., the case (and chamber!) is smaller in diameter at the mouth of the case than at the head of the case.

Thus, if you don't sufficiently remove the casemouth expansion that round isn't going to pass the plunk test--the case itself jams in the chamber as it narrows toward the throat. You might be able to successfully shoot such a round with insufficient crimp, if the slamming of the slide forward essentially "crimps" the case in chambering the round, but it's not right.

But it also is sometimes the bullet.

I shoot an XD-9 and the throat/leade is short--so short that if I use Missouri Bullet 9mm "Smallball" bullets, I have to go very short for them to seat properly. The "Smallball" has a very fat ogive, as opposed to the much more slender profile of commercial FMJ bullets. My standard OAL with those bullets is 1.085, where I reload FMJ bullets for 9mm at 1.120 or longer. You'd better believe I worked up those rounds w/ the Smallball. :)


A couple others above mentioned the crimp; it would be and is my first guess.

[Laminarman]

This is an awesome forum. Thank you. I have a bunch of reloading guides and the Lyman casting book. Are there any other good sources as far as books (I'm a reader.) I still don't know the difference between an r1 and r2. I feel stoopid : )

[Bullwolf]

This is an awesome forum. Thank you. I have a bunch of reloading guides and the Lyman casting book. Are there any other good sources as far as books (I'm a reader.) I still don't know the difference between an r1 and r2. I feel stoopid : )

As I understand things,R1 and R2 are just abbreviations for the boolit nose radius ogive. An ogive ("Oh-jive") is a curved shape, figure, or feature.

Lee Mould Number Codes:



MOLD NUMBER CODE


http://leeprecision.com/graphics/shoppingcart/chrtbull.jpg
C
309
180
R


Gas Check
Diameter
Weight in Grains
Point Shape


TL
Micro Bands for
Tumble Lubing
with Lee Liquid Alox
WC = Wad Cutter
SWC = SemiWad Cutter
RF= Round with Flat
R= 1 0give Radius
2R= 2 0give Radius
TC= Truncated Cone



Tangent Ogive
R = The radius of the curve of the ogive in inches

http://www.gunsopedia.com/images/0/0d/Secant_ogive.png
A secant ogive of sharpness
http://bin.sensegates.com/s/c/d/6/cd6d31230fe33cee9a9d447e6f6c0c5f.png


This might be information overload, but you can read a pretty good definition about it in the link below.

http://www.gunsopedia.com/Ogive

To massively oversimplify things, one boolit has a more gentle nose curve than the other.


--------------1R-------------VS-----------2R-----------------
http://www.titanreloading.com/image/cache/data/Products/90305-250x250.jpg http://www.titanreloading.com/image/cache/data/Products/90457-250x250.jpg
-------356-102-1R-----------&-----------356-125 2R-------

Someone will likely be along shortly who is able to explain the math better, or more simply than I did.

You may also find this article about nose profile feeding and reliability to be educational.
http://www.38super.net/Pages/Bullet%20Design%20and%20Feeding%20Reliability.html


Hope it helps some.



- Bullwolf

[tazman]

That's as good an explanation as I have seen and much more understandable than many.

[Big Boomer]

tazman is right ... very good explanation. A picture is worth a thousand words.

I recently purchased a Sig P938. Titegroup has this suggested data for the 9mm right on the powder can: 4.8 gr. with a 115 gr. jhp bullet, 1.125" OAL, fps. at 1158 but I am sure it was with a larger framed and longer barreled pistol. Since the Sig 938 is pretty small size-wise, I dropped that load .8 gr. to use with the Lee 120 gr. cast boolit (with my alloy - it is supposed to be a 125 gr. boolit) and it was still too hot a load. So I'm back to the drawing board and will be working down to a lower level for this pistol to make it shoot more comfortably. BTW, this load and boolit shot very accurately and right to the point of aim. Could not ask for more in terms of accuracy at 5 to 10 yds. Big Boomer

[Laminarman]

Great explanation Bullwolf, thank you! I love my P938 as my CC piece, but was trying to shoot it a lot at a more reasonable cost hence the handloads. I'll keep working at it, but it seems I have this thing called "work" that keeps getting in the way. What the heck's with that?

[tazman]

tazman is right ... very good explanation. A picture is worth a thousand words.

I recently purchased a Sig P938. Titegroup has this suggested data for the 9mm right on the powder can: 4.8 gr. with a 115 gr. jhp bullet, 1.125" OAL, fps. at 1158 but I am sure it was with a larger framed and longer barreled pistol. Since the Sig 938 is pretty small size-wise, I dropped that load .8 gr. to use with the Lee 120 gr. cast boolit (with my alloy - it is supposed to be a 125 gr. boolit) and it was still too hot a load. So I'm back to the drawing board and will be working down to a lower level for this pistol to make it shoot more comfortably. BTW, this load and boolit shot very accurately and right to the point of aim. Could not ask for more in terms of accuracy at 5 to 10 yds. Big Boomer

The Hodgdon data site lists 4.0 as a max charge for Titegroup with a 125 grain lead boolit. You basically started at the max loading.

[Laminarman]

** UPDATE: First off, thanks for all the help. I settled on a COAL of 1.085 which doesn't really pass the "plunk" test but feeds well on a full speed slide. In any event with 4.0 of WSF it shoots well and doesn't seem to jam. I'll get a chronograph and begin testing from here then try it in my STI Guardian. 4.7 of WSF and COAL of 1.169 per "the book" shoots great in my Guardian but will not feed in the P938. My hope is the new "shorty" in the P938 also shoots well in the Guardian so I can work up one load to avoid confusion. After this experience I'm not all that impressed by the shape of these bullets. I think I'll shop for the more slender profile (I don't cast my own) but have 1,000 of these and would like to use them.

[tazman]

I expect the shorter OAL will feed ok. The nose profile is too rounded to allow a long OAL. It leaves too much of the full diameter side of the bullet exposed above the case mouth.
I expect your P938 has a short throat. You could have the barrel throated but if the short OAL load will work there is no point in having it done.
WSF is an excellent powder for the 9mm with most bullet weights.

[wv109323]

Laminarman,
I am having the same frustrations that you are with the 9MM. My pistol is a CZ 75B and it has a short throat and a small bore. The RN and the RNFP bullets in a cast bullet creates problems in our pistols. The .356 or .357 or .358 diameter of the RN cast boolit hits the rifling unless seated very ,very short. As your are aware this can spike pressures quickly.
I went from the Lee 358-125 RNFP to the Lee 356-120 TC mold for the CZ 75. I needed the .358 diameter mold for another 9MM that needs a fat bullet to fit its bore. I bought the .356- 120 TC mold because it has a shoulder where the nose begins to taper. Even with this design I can leave none of the major diameter of the boolit extending beyond the case mouth, thus they are seated deep also.
I said all this to caution you that I would buy a few bullets of the same weight and profile to try before I bought the mold.