I had Erik at www.hollowpointmold.com do a cup point which I use at low velocity in the .45 Colt, .45 Schofield and .455 Webley.
I cast my bullets using 1:30 tin-lead from Roto Metals, 9 BHN. Velocity is about 700 fps.
Cavity is a full radius hemispherical cup point 0.7 of meplat diameter, so that depth is half of cavity diameter.
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Great information and impressive bullet. That is who I have been talking with and plan on doing the work. If I mimicked that Design, relative to my caliber, is it as simple as casting the boolit a little harder (using tin not Antimony)to account for the increase in velocity?
Yes, my work has mostly been in black powder handguns, but I use the loads in rifles also.
Crude swag which I have found agrees with experience is that you want BHN ~ velocity/100 so
For very low velocity under 800 fps you want 1:40 or 1:30 tin-lead 8-9 BHN
At 1000 fps your 10 BHN will be fine
At 1200 fps and above 12 BHN works
At 1400 fps and above wheelweights + 2% tin, about 13.5 BHN is fine
Not sure how this translates to higher velocities, but it works in the .44 Magnum, .44-40 and .45 Colt with traditional style flatnosed bullets of normal weight for the caliber, firing full-charge black powder loads and smokeless loads at full charge BP velocity, 700-1000 fps in revolvers and 1200-1450 fps in rifles.
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I'm shooting a 10mm in both a Glock longslide and 1911 longslide using an alloy about same as Outpost75. I'm running them at about 1100 fps. The bullet is a LEE 175 TC bullet, but with the soft alloy I'm using they run 180. I run them through my swage with a hollowpoint pin of the pent configuration and they are free checked with soda can aluminum check before swaging. The free check insures absolutely no leading at these velocities with this soft an alloy. Some I push faster along with faster 357 bullets and 9mm made the same way. The 9mm are from a Mihec hollow point mold. The hollow point on those is the round cone type. These were fired into really wet newspaper.
I am shooting into water jugs, this is typical test array, shoot through chronograph and capture round at 25 feet. Some photos of typical low velocity tests of 1:30 alloy fired in a .38 S&W snubby.
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Thanks for sharing. I've been thinking of building a hybrid Fackler box, but something that has easily removable and penetrable baffles in it to measure penetration as the boolit passes through. Maybe something like corrugated plastic-board. My initial idea is to use a sludge of water and something else, maybe fine dirt or powder of some kind to give it a little bit of consistency. Once I have the consistency I like, I could measure the weight by volume to reproduce reusing the same media. I'm still thinking about the design at the front to hold it all in but haven't quite gotten there yet. I'll post when I figure it out. More likely I'll spend a week trying to get it right and go buy water jugs at the end of the day.
Water is really hard on bullets. I had a big water tank I use to put a weighted down cardboard cover on and shoot bullets into it. The HV stuff really destroyed themselves. That newspaper I mentioned in my post was in a plastic retangular tank stacked tight and then poured water in it and let it soak the paper thoroughly for day or two. Actually had a little water in it when I shot at it. I thought it was like blood moist tissue in a way. I plugged the bullet holes with putty and replaced the lost water and shot at it somemore. I think I may build a lightly oiled sawdust trap next.
Let me ask another question. I've decided to eliminate the gas check from the mold design, so I just tried seating a dummy round using a 275gr HP I have on hand with a BHN 10, sized to .431, and removed the gas check. I pulled the bullet and found the shank to be reduced by .001 and the front band increased by .004. Obviously my case tension is too high. I know from a previous conversation with Lee that their case sizing die is intentionally designed to size at approx .425. It's a carbide die. I've searched this forum and most conversations I've seen refer to case mouth expansion, not case sizing. How are you seating those soft boolits without deforming them?
For one they are free checked using aluminum from soda cans and that makes the base and corner of base a little stronger. I make powder through expander dies and tailor my expander size to be just right with my bullets. Sometimes I make errors like any other reloader and have to pull a bullet. The ones I've pulled never showed getting sized down. Yours sound like they are really sizing down to expand that shoulder!! On a lot of my rifle dies I use bushing dies and select the proper bushing where inside neck diameter is just right for my bullet size. Too bad they don't have those for pistol/revolver dies. I'd say get the right expander sizes. I usually have the case expanded .0015 to .002 under the bullet size. Make sure you chamfer the inside of the case mouth and have a bell so to easily start the bullet. This bullet softness you and I are discussing is what I talk about the Lyman M dies leaves a shoulder than can size a very soft bullet down. If you tailor made your ow M dies they would be better. Remember most of the factory stuff is geared towards jacketed bullets.
The thing I like about free checking my soft bullets is that I can blister them in velocity and they are super explosive on small critters.
VZ
Thank you very much. This is one of the reasons I originally had the design with a gas check, but I've decided I don't want to risk it separating with a suppressor on the gun. Too costly. I just researched the M die and it sounds perfect. And Midway just happens to have the .44 on sale! It's on its way. Thanks again.
Leave one of the LGs in there to collect the moved alloy. Lose the GC, bevel base wil do fine. Spend the $ for a proper seater plug that fits the nose. You don't get springback with really soft alloy so you may need a special sizer. Paco found a small dimple point gave better accuracy in 22, extra pressure point on the nose. But the 'other' guy says WC gives best performance. NOE expander with the Lee flare setup works god and he could make you a special just for your size. I had to get a M die turned for 40sw as the factory ones are for jacketed. I don't use the step on the M type to flare, but use the Lee flare. Lyman bevel tool works great too. I was playing with Pb/Zn alloy, fun to try loading that soft stuff. Sure does expand well.
Whatever!
Really appreciate the help and advice from all. It is much quicker and less painful to learn from experienced folks than trial and error. My mold should be here in three weeks or so, and then I start my foray into casting. No doubt I'll need some guidance. I'm going to play with the mold a bit before I send it off for hollowpoint service. I'd like to get some boolits cast so I can play with the powder coating and ballistics testing while Erik is working on the mold. I'm also going to use this time to build something for terminal performance testing to help get the BHN right for penetration, expansion, etc. I read a post from someone on here a few years back that used play-doh for testing boolits. That's a fascinating idea to me as homemade play-doh is cheap and reusable. Build a long box with a hole in the front end and fill it with play-doh...we'll see.
Your design inspired me, so I built this to stuff with home made playdough. Removable top so I can cram playdough in and the sides are hinged on the bottom so I can lay the whole thing open after shooting. Not sure what to expect but would be nice if the playdough held together enough to cut with fishing line and examine the wound cavity. While waiting on my new mold I'm going to try the 275 hp's from Matt's bullets this weekend and also some jacketed as I know what they do in gel and can compare.
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |