COL with 9mm LRN Bullets

[Low Light]

Hello all. Question regarding COL variances with LRN bullets. Here's where I stand: These loads are for a Taurus PT92 using Missouri Bullet Company 115 grn. LRN bullets (.356). The Hodgdon website and the Hornady manual state that minimum COL is 1.100", only problem is that 1.100" will not seat properly. I thought this might be a crimp issue, but I've essentially ruled that out (I believe) using the Lee FCD down to it's lowest setting (tightest crimp) but the seating issue didn't resolve itself (I know that I should keep the FCD away from lead bullets but I wanted to rule out any undercrimping issues - ideally I'll be crimping with the bullet seating die set properly).

Can I safely reduce COL to say 1.080-1.090 and use the bottom end of load data (minimum charge is 3.9 grains) for Titegroup? I was planning on testing a batch at about 4.0-4.1 grains but if the decreased COL is within safe parameters I'm thinking I should lower my bottom end charge to the minimum 3.9 grains and see how that works. Thoughts? Should I go lower than 3.9 grains? Is going below 1.100" even do-able? Is the "plunk test" in combo with the lowered COL still a good measure?

Thanks, in advance.

[UnknownShooter]

Hello all. Question regarding COL variances with LRN bullets. Here's where I stand: These loads are for a Taurus PT92 using Missouri Bullet Company 115 grn. LRN bullets (.356). The Hodgdon website and the Hornady manual state that minimum COL is 1.100", only problem is that 1.100" will not seat properly. I thought this might be a crimp issue, but I've essentially ruled that out (I believe) using the Lee FCD down to it's lowest setting (tightest crimp) but the seating issue didn't resolve itself (I know that I should keep the FCD away from lead bullets but I wanted to rule out any undercrimping issues - ideally I'll be crimping with the bullet seating die set properly).

Can I safely reduce COL to say 1.080-1.090 and use the bottom end of load data (minimum charge is 3.9 grains) for Titegroup? I was planning on testing a batch at about 4.0-4.1 grains but if the decreased COL is within safe parameters I'm thinking I should lower my bottom end charge to the minimum 3.9 grains and see how that works. Thoughts? Should I go lower than 3.9 grains? Is going below 1.100" even do-able? Is the "plunk test" in combo with the lowered COL still a good measure?

Thanks, in advance.

I use this gauge for my "plunk" test:

http://www.amazon.com/Lyman-Reloading-Luger-Pistol-Cartridge/dp/B005I0ITGO

I'm wondering if something else is happening in the process to keep your bullets from seating? With W-231, I've gone down below spec for COL, in the area of 1.065", but 231 is a fast, spikey powder, and titegroup is supposed to be even faster.. personally, I wouldn't go that low with the COL unless it was a minimum load, based on mfr data..

[RugerNo1]

What do you mean by "will not seat properly?"

On my lead pistol loads, I crimp on a separate station because the crimping function of the seating die sometimes deforms the softer bullets.

[Low Light]

What do you mean by "will not seat properly?"

They sit farther out of the chamber - I pulled the barrel out to test - than factory rounds. Doing a rough gauge with the plunger on the calipers they sit about .020" farther out than the factory rounds (115 grn FMJ's -not LRN's). Plus they don't fall into the chamber or fall out very easily.

I guess another question might be how much farther out can they sit (since they are LRN's)? These are set to a COL of 1.100" with a crimp of 0.375" with a .356 bullet. It seems as though the bullet is hitting the barrel before being properly seated, even at minimum COL.

I take it lead rounds aren't supposed to sit farther out (even though the profile versus an FMJ is different)? IOW a lead round should chamber just the same as an FMJ (i.e. via the "plunk test")?

[Bill Steele]

It sounds like what is happening is the wider bearing surface (the flat part before you get to the ogive) is jamming into the throat of your gun (a very common occurance with lead bullets and tight throats). Essentially the round is headspacing on the bullet rather than the case mouth.

As you suspect, you can seat the bullet deeper until the round will headspace on the case mouth. If you go this route and it takes you below the minimum OAL for the load spec you may have pressure issues. If you go this route, definitely use start loads and work up slowly. The negative with this approach is you may experience feed issues coming out of the magazine if the round gets too short.

Another approach is see if the gun will go into battery with the round headspacing like it is on the bearing surface jamming into the throat. If it will go reliably into battery, you can choose to ignore the tight fit in the throat and shoot away. Many shoot lead with this condition with no ill effects. Best to use start loads again and work up slowly.

The final solution is to take your barrel to a good smith and have him throat it for lead. It doesn't take much work in the throat area to accomodate lead for most barrels.

Good luck, have fun.

[Low Light]

Yes, one thing I have not done is try to see if a few dummy rounds will cycle. My only concern if they do is, have I crossed a line even with a minimum charge with a fast-burning powder like Titegroup and a "below-spec" COL?

Is there a "line-in-the-sand" when going below minimum COL? I suppose you can go till you cycle properly, but at what point do pressure issues become a real concern?

I'll throw a hypotethical out there: am I OK at, say, 1.080" at 3.9 grains?

Thanks all, for the help; so far.

[Bill Steele]

The pressure curve is not linear, that is a 10% reduction in powder results in a greater than 10% reduction in pressure (vice versa ia also true, that is why max loads are so important), so using start loads should be fine for a .020" reduction in OAL under minimum.

There are a few guys on these boards that run quickload software, maybe one of them will happen along and verify the numbers.

If it were me, I would first check and see if the gun will hand cycle and go reliably into battery at the minimum OAL before contemplating deeper seating. I would then work up from your 3.9grs to where I wanted velocity wise.

PS - When fooling around with lead bullets and a gun with a tighter throat, you can get a jam where the gun fails to go into battery and yet the slide seems locked into position (just out of battery). In this case it is good to know the proceedure to clear this jam (other than prying things open with a screwdriver, etc.). The thing to do is with the gun pointed in a safe direction, hold the slide with your weak hand, and slam the crotch of your strong hand into the top of backstrap (right where you grip it), this will usually break the slide free.

[Low Light]

If it were me, I would first check and see if the gun will hand cycle and go reliably into battery at the minimum OAL before contemplating deeper seating. I would then work up from your 3.9grs to where I wanted velocity wise.

PS - When fooling around with lead bullets and a gun with a tighter throat, you can get a jam where the gun fails to go into battery and yet the slide seems locked into position (just out of battery). In this case it is good to know the proceedure to clear this jam (other than prying things open with a screwdriver, etc.). The thing to do is with the gun pointed in a safe direction, hold the slide with your weak hand, and slam the crotch of your strong hand into the top of backstrap (right where you grip it), this will usually break the slide free.

Well, I guess I've hit a wall. Out of 20 dummy rounds with COL's ranging from 1.078" to 1.100" and corresponding crimps ranging from 0.373" ot 0.377", in too many combinations to recall, not a single one cycled reliably (btw, thanks for the jam clearing technique, Bill, used that one at least 5 times during the process).

Any tips/advice from anyone with a Taurus PT92 loading 115grn LRN's (other than reaming out the barrel), would be most welcome.

This is one of the earlier models built on Beretta machinery, so 92F/M9 tips/advice might translate.

Thanks all, either way.

[Bill Steele]

Well, I guess I've hit a wall. Out of 20 dummy rounds with COL's ranging from 1.078" to 1.100" and corresponding crimps ranging from 0.373" ot 0.377", in too many combinations to recall, not a single one cycled reliably (btw, thanks for the jam clearing technique, Bill, used that one at least 5 times during the process).

Any tips/advice from anyone with a Taurus PT92 loading 115grn LRN's (other than reaming out the barrel), would be most welcome.

This is one of the earlier models built on Beretta machinery, so 92F/M9 tips/advice might translate.

Thanks all, either way.

When seating the deepest one you tried, does the bearing surface protrude above the case mouth? If yes to the foregoing, I would seat one down far enough so the bearing surface doesn't sit up above case mouth. This should allow the round to drop cleanly into the chamber.

A crimp closer to .377" is what you want (depending on how thick the brass is, basically just straight, no clamping of the bullet at all).

At the above seating depth, definitely use a start load level.

[Low Light]

When seating the deepest one you tried, does the bearing surface protrude above the case mouth? If yes to the foregoing, I would seat one down far enough so the bearing surface doesn't sit up above case mouth. This should allow the round to drop cleanly into the chamber.

A crimp closer to .377" is what you want (depending on how thick the brass is, basically just straight, no clamping of the bullet at all).

At the above seating depth, definitely use a start load level.

Wow that low, huh? Looking at where the crimp dug into the bullets I pulled (I ended up pulling all of them last night) the lowest one looks like it was maybe .010-.015" below the top of the bearing surface, Bill.

Seating deeper would put it down to about 1.065, maybe 1.060". That low huh? Slightly scary stuff, no?

Thanks, btw.

[bohoki]

yea i load them somewhere between fitting in the magazine and fitting in my chamber your length may vary

[Bill Steele]

Wow that low, huh? Looking at where the crimp dug into the bullets I pulled (I ended up pulling all of them last night) the lowest one looks like it was maybe .010-.015" below the top of the bearing surface, Bill.

Seating deeper would put it down to about 1.065, maybe 1.060". That low huh? Slightly scary stuff, no?

Thanks, btw.

In my guns that have tight throats, I never load lead with the bearing surface more than 1/16" above the case mouth. In some loads I make sure the bearing surface is ending right at the case mouth. The bearing surface is .356" wide so it jams in the throat. Ironically, any crimp actually makes the bearing surface above the case mouth wider as it squishes the lead up, making the jamming problem worse. Try it flush with the case mouth.

If you take the max load and reduce by 10%, you will be reducing the pressure by something closer to 15%, so a start load should be fine. Just measure carefully on the first ones to make sure you are at start levels. After you get that working, move up in .2gr increments until you start seeing pressure signs.

Hang in there, you will get it working.

[CGT80]

You shouldn't have to crimp. I got the most consistent results running moly coated bear creek lead bullets with almost no crimp. When I pulled the bullets, you could only see a faint discoloration where the edge of the case mouth was, but you couldn't feel it. My standard deviation was about 7 fps on a load that was around 1,000 fps.

My crimp die was set to just remove the flare/bell from the case mouth. I have no problem seating as deep as the chamber requires. I also use the lightest load that gives reliable function and accuracy in my semi auto pistols, and that is usually less than even the middle of the recommended load range.

I also had my Barsto barrel finish reamed and tapered so that I could load my ammo to a length that my mags like. My smith didn't even charge me for that work, as I bought that barrel from him and payed to have him hand fit it to my pistol. It took him less than 15 minutes to touch up the chamber. It did not effect my accuracy enough to notice it in pistol competitions and it made the barrel reliable with reloads.