Cast boolits and brass life

[selmerfan]

So I'm just wondering - do cast boolit loads work-harden brass any less than full-power jacketed loads? For comparison, think .260 Remington, 130 gr. cast GC with 15 gr. 2400 vs. 129 gr. Hornady Interlock SP with 44 gr. IMR 4350 behind it - same gun. I've been shooting a lot of cast loads in my .260 Rem and .30-40 Krag and I wonder if I should be annealing every third or fourth loading of cast like I do with jacketed? Thoughts? I'm sure I'm not the first to wonder...

[mdi]

I have been around here for a while and have never heard/read of any difference in case life jacketed vs cast. I don't reload for bottle necked cartridges, yet, (have the mold, have gaschecks, but awaiting dies) but the only wear factor in handgun cases would be excessive crimping, lead bullets being crimped more than jacketed...

[tomme boy]

Where you are going to run into problems is the dies are made for jacketed bullets that are smaller diameter than cast. So everytime you size them, they are being sized too small in the neck. That is what is nice about the Lee collet die and other types of collet dies. You can adjust the amount of sizing that can be done to the neck. Lee is nice as you do not have to buy different sizes of collets for the die. Limit the amount of belling of the mouth and the cases will last a very long time. When I lose one, it is cracked from the mouth down.

[selmerfan]

Interesting. I had not known that Lee College dies were adjustable for the amount they sized down the neck. I currently have removed the expander ball from my resizing dies. Then I bell them with a lyman M die. theoretically they are sized a little bit less because I'm not running them over the expander ball then over the M die

[Four-Sixty]

The Lyman M die is an awesome tool for CB in the rifle.

[Doc Highwall]

Having a tighter match chamber one not requiring neck turning, the case neck does not get a chance to expand as much as say a military gun that was made during a war time conflict meaning that the case neck does not have to be sized down as much. When you have a gun with a chamber with that has a larger neck diameter it will require that the cases will have to be sized down more, even with lighter cast bullet loads the brass will still expand. Then you have to take into account that most dies are made for jacketed bullet diameters, and that cast bullet shooters are shooting bullets that are .001"-.002" larger that the dies are not sizing you brass at least .001"-.002" too small. It may not seem like much but this is enough to work harden your brass.

When I reload for cast bullets I have a set of cylinder plugs / pin gages to check the I.D. of the fired cases and sized cases, and I use Redding bushing dies so I know how much the case necks are being sized down. I also make my own neck expanders so I know how much neck tension that I have when the known size cast bullet is seated.

The over working of the brass in the firing and resizing work hardens it more then high pressure loads, but then high pressure loads in the same conditions do contribute some to work hardening of the brass.

[Larry Gibson]

No, most cast bullet loads do not work the brass as hard as full bore jacketed loads. You should not have to anneal the case necks but maybe after 10 - 15 firings. As mentioned chamber neck clearances and how much your dies size down the necks have a lot more to do with work hardening the case necks than the actual load used. A bushing or collet neck sizing die that you use the correct sizing bushing or adjust to give .003 max neck tension will greatly increase case life, especially with cast bullets. Using such I seldom anneal case necks anymore because of simple sizing. Have cases that have been loaded 20-30+ times with no sign if neck fatigue.

Larry Gibson

[selmerfan]

So for my .30-40 Krag I'm using a set of Lee dies - FL sizer, seater, and FCD. My Krag is a single-shot barrel for my Stevens 44 1/2 - I'm only sizing the top 3/4 of the neck. I wonder if I need to be sizing the neck at all? I lightly crimp the loads - would that give me enough neck tension, or do I need to size down the neck to ensure consistent ignition and tension? I know the answer is "measure it and find out", but I'm at the office so I'm just thinking out loud. I'll check it out later this afternoon/evening. My .260 Rem is a Ruger M77 and while not a sloppy chamber, it's not a match chamber by any means.

[john hayslip]

I know several schutzen shooters who push the bullet in the barrel and put a case of powder behind it. There cases last for hundreds if not thousands of rounds as the brass is not worked . They are usually retired because the primer pocket has been expanded due to friction and won't hold the primer any more. Most of the cases have a notch filed into the rim so the case can be inserted into the chamber the same way each time. It's the reloading dies that cause the short life span, not the type bullet.

[selmerfan]

Yes - breech seating. I didn't order this barrel set up as a breech seating barrel, but there is probably no reason I couldn't seat the boolits long, then use the camming action of closing the action to seat the bullet and jam the lands, which is essentially what breech seating does.

[Doc Highwall]

selmerfan, you say you only size 3/4 of your neck and my question is how much below the base of the bullet is this. I do not crimp any of my single shot rounds but the bullet is touching the lands on a loaded round for start pressure. Have you tried shooting them with out a crimp as that will add to work hardening.

[selmerfan]

Okay, came home for lunch and did a little work at the bench. First of all, I can't get away with loading without sizing - boolit slips in - not loose, but won't stay in place reliably. Second, I did some die comparisons. Interesting that different .30 caliber resizing dies size necks differently. I have .30-40, .30-06, and .308 Win on hand for sizing dies and I set up each sizing die to size only 3/4 of the neck on my .30-40 Krag brass. The Lee .30-40 die sized it down the most, the RCBS .308 Win die the least and had zero runout with the .308 Win die. The Lee sized it down 10 thousandths more than the .308 Win! I have not tried not crimping the loads. I'd thought about not seating into the lands, but can't remember why I didn't... For a test run, I still have 20 rounds of 17 gr. 2400 loaded up, lightly crimped, neck sized with the Lee die. I will load up 10 rounds of 17 gr. 2400 with the .308 Win-sized cases and seat the 311299 to touch the lands and compare precision and POI. IIRC, I may have them seated out to the lands anyway - when I sent my frame in for barrel fitting to CPA I sent in a few of the 311299 boolits I intended to use. I think they may have throated it to seat into the lands when the boolit is seated to the crimp groove, but I'll check later - I need to get my sermon written! :)

[selmerfan]

I forgot to answer your question about sizing and the base of the boolit. It appears that the sizing stops right at the base of the boolit - I just chose an arbitrary point, so it was a random point, but I'm questioning if I should size just a bit farther down so it's all consistent. Then again, 90% of the loads I've tried in this barrel shoot MOA, and the ones it likes make big black holes in the target with 10 shot groups, as in 1/2 MOA at 100 yds, so I can't be doing too much wrong. :grin:

[Doc Highwall]

Your accuracy sounds great. I think that the neck should be sized a least the length of the bullet seating depth plus .050" and the expander should also go .050" past where the base of the bullet is when it is seated so as to provide bullet tension along the entire seating depth. The small bell on the case mouth I usually leave on the case or maybe just enough crimp to remove the case mouth bell.

[selmerfan]

"Just enough crimp to remove the case mouth bell" is actually my "really light crimp". I'm sizing the neck almost that much - I could got a bit farther. I'm using a Lyman "M" die expander, so it should be expanding the neck pretty much just right. Here are some of the targets - all of these were shot at 100 yds from a bench. Not a whole lot of room for improvement...
http://i633.photobucket.com/albums/uu58/selmerfan/Mobile%20Uploads/image_zps0abad3e7.jpg (http://s633.photobucket.com/user/selmerfan/media/Mobile%20Uploads/image_zps0abad3e7.jpg.html)

http://i633.photobucket.com/albums/uu58/selmerfan/Mobile%20Uploads/image_zpsb3266b02.jpg (http://s633.photobucket.com/user/selmerfan/media/Mobile%20Uploads/image_zpsb3266b02.jpg.html)

http://i633.photobucket.com/albums/uu58/selmerfan/Mobile%20Uploads/image_zpsac79c88e.jpg (http://s633.photobucket.com/user/selmerfan/media/Mobile%20Uploads/image_zpsac79c88e.jpg.html)

http://i633.photobucket.com/albums/uu58/selmerfan/Mobile%20Uploads/image_zpsf6eba69e.jpg (http://s633.photobucket.com/user/selmerfan/media/Mobile%20Uploads/image_zpsf6eba69e.jpg.html)

20 gr. RL7 - .30-40
http://i633.photobucket.com/albums/uu58/selmerfan/Mobile%20Uploads/image_zps5a107f26.jpg (http://s633.photobucket.com/user/selmerfan/media/Mobile%20Uploads/image_zps5a107f26.jpg.html)

http://i633.photobucket.com/albums/uu58/selmerfan/Mobile%20Uploads/image_zps7d4725d4.jpg (http://s633.photobucket.com/user/selmerfan/media/Mobile%20Uploads/image_zps7d4725d4.jpg.html)

http://i633.photobucket.com/albums/uu58/selmerfan/Mobile%20Uploads/image_zps3fba1b08.jpg (http://s633.photobucket.com/user/selmerfan/media/Mobile%20Uploads/image_zps3fba1b08.jpg.html)

[Doc Highwall]

selmerfan, what size are the bullets you are shooting and what is the diameter of your Lyman M die? Also is the length if the M die that expands the neck at least as long as the seating depth of your bullet into the case neck?

I had some RCBS and Lyman expanders that were too short by at least .100" for the 30-30 Winchester due to the long neck and your 30-40 has a even longer neck.

[Tatume]

A friend of mine at University of North Carolina decided to test brass life in 38 Special using wad cutters and target loads. He started with 100 new cases. I think the experiment has turned into a life-long project. :-)

Take care, Tom

[DeanWinchester]

I used to use the M die for my .308 loads until I just started adjusting a collet neck sizer to tension I need. I use a Lee case flaring tool and a factory crimp die to close the bell. I recently retired a lot of (50) Hornady Match brass. I annealed twice throughout it's life. I had OVER 50 loadings on the lot. Only reason I set them under the bench was because I bought a brand new rifle.

I don't know the answer to your actual question, sorry.