9nn Seating depth?

[milprileb]

The 120 grain Lee TC style bullet has me a bit stumped. :killingpc:killingpc:killingpc

Does any one load this 9mm bullet and could you give me your OAL for loading this bullet?

[LubeckTech]

Funny you should post this question as I had almost exactly the same question on my mind for the past few days. Difference is my bullet is the TL SWC style of that bullet. Great minds think alike!!

The answer to our question ti to be found here;

http://www.castboolits.gunloads.com/showthread.php?t=115157&highlight=9MM+OAL+356-120-TC

A fine thread on this subject.

[MtGun44]

I use 1.075" with that boolit. What is the issue? Short enough to chamber and fit into the
magazines but no shorter is my starting point with most semiautos. Light TC is usually a
requirement for reliable chambering, a critical issue for .45 ACP and one of the most common
issues for fail to feed in that caliber. I just set up my 9mm the same way and never had any
issues, feeds and accurate in many different guns.

Bill

[milprileb]

Well Bill, the closest Lyman TC bullet in 120 gr for 9mm is a COAL lenght of 1.110 and
my chamber won't take the Lee bullet seated that far out and round hang up
in magazine . I can seat it at 1.100 and get
decent accuracy and function. 1.090 , 1085 and 1.076 are scattered shots and some leading. I am Leary of going below 1.076 as pressures soar and I am not sure the thread mentioned is a good reference: some go to 1.066.

Guess there is no school answer here and I am into discovery learning again.

[GabbyM]

That Lyman 356402 bullet has a long nose. Not sure about the Lee TC bullet but with a Saeco 122gr TC seated at 1.050" is takes up the same case capacity as the Lyman bullet seated to book length. That's the laod data I use for my Saeco bullet.

[HammerMTB]

Hmmm
I just tried out some of these. In my P89 they filled the mag at 1.160
Didn't feed 100% there. I moved to 1.110
I think that will be better. Vels ran right at 1100FPS

[fecmech]

Well Bill, the closest Lyman TC bullet in 120 gr for 9mm is a COAL lenght of 1.110 and
my chamber won't take the Lee bullet seated that far out and round hang up
in magazine . I can seat it at 1.100 and get
decent accuracy and function. 1.090 , 1085 and 1.076 are scattered shots and some leading. I am Leary of going below 1.076 as pressures soar and I am not sure the thread mentioned is a good reference: some go to 1.066.

Guess there is no school answer here and I am into discovery learning again.

There is no pressure problem with the Lee at 1.055. You have exactly the same case capacity as the Lyman at 1.110. The Lee bullet has the same bearing surface as the Lyman. If you will read the thread link posted by Lubeck tec it will explain.

[milprileb]

But when I seat this bullet deeper as stated, I begin to get leading. Now is that pressure or is that bullet jump? The accuracy degrades the deeper I seat the bullet.

Bearing surface aside: you are telling me a 120 grain bullet seated 1.110 and one seated 1.055 will yield no increase in pressures ? Then why does Lyman list 1.110?

I am not gripping where you are coming from so please explain. I just got to ask before I try it.

[sig2009]

I load mine to 1.045 and have no problem chambering in any of my guns and is very accurate with 4.0gns Bullseye.

[milprileb]

SIG2009: may I ask what is your alloy ? I found BE to be too fast a powder and promoted leading. However that pertains to 9mm , in 45acp, I have always had great success with BE and cast bullets.

I assume your 1.045 is with a 120 gr Lee TC bullet ?

Thanks for posting, very interesting stuff !

[sig2009]

SIG2009: may I ask what is your alloy ? I found BE to be too fast a powder and promoted leading. However that pertains to 9mm , in 45acp, I have always had great success with BE and cast bullets.

I assume your 1.045 is with a 120 gr Lee TC bullet ?

Thanks for posting, very interesting stuff !

Sorry I didn't mention I am using Kead Bullets 120gn tc sized to 356.5 and have no leading. I am tired of using the lyman 2 cavity molds and was looking to buy the lee 6 cavity 120gntc mold.

[garym1a2]

I go about the same lengths at 1.075 or so. I use WSF and get great results. Orginally I though I need to go at 1.04 and had a lot more velocity variations.

I use 1.075" with that boolit. What is the issue? Short enough to chamber and fit into the
magazines but no shorter is my starting point with most semiautos. Light TC is usually a
requirement for reliable chambering, a critical issue for .45 ACP and one of the most common
issues for fail to feed in that caliber. I just set up my 9mm the same way and never had any
issues, feeds and accurate in many different guns.

Bill

[whopist]

I read all the 9mm load overall length threads I find because I also have an accuracy and leading problem with my Sig P6. This P6 is my only 9mm pistol with this problem.

This might help you. It is something to look at anyway.

My 9mm Lyman M Expander Die was worn (it has seen a lot of use). It was not expanding my brass large and deep enough. I should also note the button’s first step had worn to a taper. See the dimensions in picture
http://i264.photobucket.com/albums/ii165/whopist/WornExp.jpg

Top boolit: Saeco #377, .358”x122g TC
Middle boolit: Lee #356-120,.358”x120g TC
Bottom boolit: Lyman #356402, .358”x120g TC


The worn expander button was replaced with a Lyman 38P button for 38/357 because I had it. I can now seat boolits deeper with less leading and more accuracy.

Please remember, as you reload boolits deeper you might need to reduce the powder a little! My latest 9mm OAL was 1.02" with the Saeco 122g boolit.

Hope this helps _________Good luck!

[fecmech]

But when I seat this bullet deeper as stated, I begin to get leading. Now is that pressure or is that bullet jump? The accuracy degrades the deeper I seat the bullet.

Bearing surface aside: you are telling me a 120 grain bullet seated 1.110 and one seated 1.055 will yield no increase in pressures ? Then why does Lyman list 1.110?

I am not gripping where you are coming from so please explain. I just got to ask before I try it.

The Lyman bullet is .625" long with a .280 bearing area, the Lee bullet is .560 long with a .280 bearing area. If you load the Lee to 1.055 you will have the same amount of bullet in the case ( same case capacity) as the Lyman at 1.110 and pretty much the same pressure. The Lyman bullet just has a longer narrower nose, that's all.

The 1.055 OAL will give you similar ballistics to Lymans data, I used 1.065 in my BHP for accuracy reasons. BTW I had no real leading issues in 3 different 9's with that bullet at that approx OAL.

[Cherokee]

I cast and shoot a lot of the Lee 356120TC (conventional lube) @ 1.055 OAL for my 1911. Good performance, only trace leading that cleans up with a brush. I push these to 1300+ fps in Super 38 with the same good results and only trace leading.

[MtGun44]

My normal method for setting up the initial try at setting LOA is that I hold up a factory
ball round next to my sample round and adjusted the LOA until the leading corner of the
non-ball boolit/bullet falls onto the contour line of the ball bullet. I do this for all semi-autos
and all bullets/boolits. It seems to work real well for me.

I'll add some pix in a few minutes.

OK, see if this helps with the method I use to set up initial LOA. I rarely need to change it
after setting it up this way. The pic is not exactly perfectly lined up, but I think it shows
the idea. The second one is a side view to just show what they look like
side by side. Note that the full diameter portion of both projectiles ends at the same place,
at least as close as I can tell by eye. Of course, checking whether this will fit the mag and
then chamber properly are the next tests and are absolutely critical.

http://castboolits.gunloads.com/picture.php?albumid=161&pictureid=4223

http://castboolits.gunloads.com/picture.php?albumid=161&pictureid=4224

Bill

[HammerMTB]

I just finished an experiment with this today.
With the 120TC Lee, I had tried 1.160". This was the longest that would fit in the mag. I had a few FTFs, generally tipped up but boolit nose stuck in the back end of the throat.
I got chrono data anyway, as most of them would work, prolly 1 in 10 did not.
Then I shortened them to 1.110"
Ran them again. Now they feed 100%! Success there! :2_high5:
Now an interesting sidebar:
I expected a small increase in PSI and velocity. I wasn't sure I would even detect the PSI increase, but figured it should show up as vel.
Not so.
The figures from the longer seating depth were so identical to the shorter length, if they were not labelled you'd never know which is which. 2 powders, IMR700X and Bullseye were tried. Same results in each. The Bullseye was more consistent, so it will be the go-to load for the lead boos.
I worked up a SD load at the same time, but those are JHPs, so I'll leave them out of the cast discussion.
Thought it might spur some interesting discussion..... :popcorn:

[evan price]

I was going t osay I use the 105-SWC at 1.10" and it works great in my P6... but I can attest that a small seating change when powder loads are reasonable will not cause undue changes. If you were loading at max is when the seating depth is really important.