9mm seating depth

[Tumtatty]

I've just made my first 9mm boolits!

I have a few more questions:

The length is shorter than the my factory rounds (my cast boolits are 125gr and the factory are 115gr)

1) I put 5gr of green dot in them. When I seat the boolits they are surely compacting the powder somewhat. Is that normal?

2) The OAL of my cast boolits if I sink all of the lubed ridges is 1.118"
The OAL of the factory rounds is 1.160. These are both well below the max OAL (1.169). My concern is that i may be compressing the powder too much. If so, is it ok to have some of the lube bands above brass?

http://i5.photobucket.com/albums/y164/tumtatty/boolits.jpg

[beagle]

It's fine if they'll feed through the magaine and chamber all right.

So little is published on seating depths for cast bullets that you can't always find a seating depth for your particular bullet and have to "wing" it.

In this case, I normally load dummy rounds and fool with the depth until I get functioning. Then I take the published weight of powder for the weight bullet I have and cut 20% and give it a try.

By chronographing, I can sneak up on a safe load for that seating depth. Then, I always record the SD for future use./beagle

[Cloudpeak]

I have no experience with your powder or load but I do load the Lee 124 gr RN bullet and load to a COAL of 1.115" and it feeds great through my M&P. I've never had a FTF in this gun. I've used Clays and W231 for my loads.

My bullet is the TL bullet. If you try to seat it to a longer length, you could run into trouble with the band on the bullet hitting your rifling and headspacing on the bullet as opposed to the case rim.

Cloudpeak

[leftiye]

You want to seat the boolit out so that the scraping band is just into the rifling when the cartridge is chambered (reads headspaces on the boolit in the rifling). Way to do this is to seat the boolit way out, and put it into the chamber (barrel out of gun). If it is too long for the action to close (sticks out past the rear edge of the barrel), then make it shorter and try again until it fits. I guess you could just try chambering and shortening until the action will close. Now if that length cartridge will fit in your magazine, you're good to go.

If it is convenient to get close to that length overall and crimp into the back edge of the front side of a lube or crimp groove (rear of a driving band), then that is an excellent way to stop "telescoping" (boolit being driven back into case by recoil and chambering forces), plus it is a non deforming crimping technique. Ideally you would get a boolit mold that casts a boolit of the shape that will do both- crimp into a groove, and headspace on the ogive or front driving band.

Make good and sure that your boolit isn't thick enough that the cartridge is hanging up on the chamber neck. Thickest boolit that will chamber with a couple of thou clearance is good. Better still, slug your barrel. Acouple of thou over groove diameter should be fine to size your boolits to, if it still chambers.

[Harpman]

I would rethink shooting a compressed load, especially if you have not fired the same powder amount already, I seated my bullet ever so slightly deeper hardly noticeable to the eyes, but I;ll be darned if that pressure did not rise alot....I am new to 9mm reloading, but one thing I learned immediately was do not compress loads unless you know exactly what will happen before you fire it.

[9.3X62AL]

No experience with Green Dot at all. If you have access to a Speer Reloading Manual, I suggest you read the text concerning the 9mm Luger. The short version is that the technicians at Speer intentionally loaded a proven safe-pressure load in 9mm to a .030" shorter overall length. Results were pressure readings that jumped from the safe 32K PSI level to 62K PSI.

I don't know the source of your "5.0 grains of Green Dot" data, but if I were you I would take a look at the Alliant powder website. It shows data for the 125 grain lead boolit--5.2 grains of Green Dot, and (MUCH more importantly) 1.15" MINIMUM overall length. The compression of the powder may or may not be hazardous in and of itself--but you have seated the bullet .032" deeper than the Alliant data calls for, and atop a "book" near-maximum charge. In my opinion, there is the potential for hazard here when viewed in the context of the Speer Manual text.

My thoughts........from the photo, it looks like this boolit can't be seated out much further than it currently is without impacting the rifling leade as described in a post above. That's OK, it will likely FEED safely and reliably--BUT YOU MUST RE-WORK THE POWDER CHARGE BEFORE FIRING THE ASSEMBLED CARTRIDGES. If you have some empty brass left, reduce your powder charge AT LEAST 10% (0.5 grains), and I would advise 15% (0.8 grains). Load 5-10 of these at 4.2 grains/Green Dot; see how they run.

In the Dark Ages, the idea for loading lead boolits in autopistols was to achieve reliable function, and little more than that in terms of velocity. The rationale was based on the prevention of leading, but if the boolit fits properly the leading issue largely goes away.

No need to limit yourself that severely--but go slow in raising powder weights from the start load. Be certain that fired boolits fully exit the barrel after each shot. IMPORTANT--load only one round at a time during this testing cycle, from the magazine. If the fired shot locks the slide back on the empty magazine, there is a good chance that the boolit exited the barrel--and it indicates a good load that should reliably cycle the pistol. If the slide does not lock back but does eject the fired casing, this indicates the need for a bit more powder--and I would check for a boolit in the bore (not too likely, but check anyway). If the pistol fires, and the slide traps the fired case in the chamber or between chamber and breech face ("stovepipe"), this indicates the need for a bit more powder and you better DAMN SURE check for a boolit in the bore.

If all goes well--and you really need a chronograph to infer pressures in this project--go to 4.4 grains--5 to 10 rounds--fire and assess. In absence of a chronograph, look for fired primer characteristics that imply "high pressure"--flattened radius at the edge near the primer pocket corner, cratering around the edge of firing pin indentation, overly loud report, overly brisk recoil impulse, or overly vigorous ejection (compared to factory rounds). These are all notoriously inaccurate measurement tools, but if that is all you have.....well, there you are. Any of these indicators could be a danger sign.

If things look good so far--go to 4.6 grains of Green Dot. See how they run. I'm sure you see a method/pattern emerging here. From this point on, I would increase powder charges by 0.1 grain increments at a time until the desired performance level is achieved--or some indication of over-pressure is observed. BACK THE LOAD OFF TO THE PRIOR SAFE LEVEL, and make a zillion of 'em if the spirit so moves you.

Neither the 9mm Luger nor the 40 S&W is a "beginner caliber", jacketed or cast.

[Tumtatty]

This is the help I needed! Thanks guys. :drinks:

I will set these rounds aside and work with 4.2 gr of Green Dot.

I have the SPeer and Lee manuals. Lee states a min of 5.0gr and a max of 5.2! This was worrisome to me.


Also I will adjust the boolit seating depth to 1.15 and check how these load/fire (1 at a time).

[Harpman]

I ended up finding my OAL first, then I figured how much powder to make it where the bullet just sits on top of the powder, then checked the load manuals to see where that powder amount fell, and it was right at the lower end, the start point for N340.

[MT Gianni]

Al has given you some great advice. It appears that this is a tumble lube bullet from Lee, if so there is no problem with an exposed lube groove if lubed with their liquid alox. Not the case with conventional lubes. Gianni

[Tumtatty]

This is a tumble lube bullet.

Another question: How much of a bullet needs to be inside the case for it to be held effectively? I have a 303 with a large gap between the bullet and the rifling. How far up can it be seated and still work properly?

[HORNET]

How much boolit you need inside the case depends on what you intend for them to withstand. I've got some loads intended for varmint/target that barely have the entire gas check inside the case neck. They require gentle handling and single loading. The old standard used to be 1 caliber of length for a case neck at minimum to withstand more robust handling needs. Depending on how the fit is to the barrel and the load involved, sometimes boolits can shoot well despite a "jump" into the rifling. BTW, congratulations on your first cast 9mms.

[leftiye]

Yer biggest seating issue (other than safety = concerning a too short loa for the charge as originally loaded) is preventing boolits from being pushed back into the cases. Longer equals lower pressures for any given charge. I use several different 9mm boolits crimped into the lube groove with the mouth of the case against the front wall of the groove. This leaves only the rear driving band in the case. Has worked flawlessly so far (30 years). Makes a nice looking round that does all of the above with both the Lee and Lyman 125 grain rn boolits.

[lv2tinker]

""This is a tumble lube bullet.""

I'm thinking about buying that pitucular LEE Tumble Lube mould, TL356-124-2R but was woundering what the dementions of that boolet was.

Overall Length=
Nose to front band=
Front band to rear of boolet=

Also, what Dia. is your mould casting this boolit?

Thanks,

Al

[Tumtatty]

Here's my best attempt at measuring:

Overall Length= .602"
Nose to front band=about .342"
Front band to rear of boolet=.260"

Also, what Dia. is your mould casting this boolit? .358-.359

[Tumtatty]

Ok I scrapped all the boolits I made in the first batch (will recast later).

I adjusted the OAL to 1.153 and tried them in the Glock (lone wolf) barrel. They fit just fine! I loaded 4 in a clip and cycled them through and each one seemed to feed just fine and ejected smoothly.

http://i5.photobucket.com/albums/y164/tumtatty/boolit2.jpg

Tomorrow I hope to fire them. I made loads at 4.2 , 4.4 , 4.6 , 4.8 , 5.0 gr of Green Dot. I made 5 of each and will find out what load cycles the pistol. Is the lowest that cycles the load i am after.

These rounds are strictly for plinking. I don't hunt with my Glock (or at all for that matter).


I'd like them to be accurate. I don't need much more than 10 yards out of them for the most part.

What does leading look like in its early stages? Is it easy to spot?

[lv2tinker]

Thanks, Tumtatty, that realy helps. Think I'll go ahead and order the molds.

Al