How much empty space is too much?


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monstrosity_73
January 20, 2010, 10:03 PM
I'm loading .44 mag loads with W296. I'd like to seat the bullet closer to my lands, but I'm having trouble finding info on how much empty space is too much. I'm loading for a TC contender with a 14" barrel. Hornady says 21.0 to start 23.2 max. I haven't started loading yet, so I haven't worked up to anything. Since there is no info for loading the 265 gr FTX other than net info for 1894 rifles or Revolvers with short OAL's, I plan on using the data for the 265 gr FP and work up from there. Looking at the dimensions of the .445 supermag, and comparing with the depth to my lands, it looks like I could shoot that round if it was safe. Not planning that, but I'm thinking of writing Thompson to see if the contender can handle that. I've put 23 grains in a shell and measured to the powder to see how much of the bullet would be in the shell without compressing the powder. That would be .532, which with the FTX's length of 1.035, would give me a COL of 1.777". I have clearance of 2.045 to the lands. I can't get my ogive close to that due to the shortness of 1.275 long brass. This is why the .445 has my attention. What if I loaded a .44 mag charge with this bullet in a .445 case? So, if I seat my bullet to an COL of 2.035, this puts .275 in the case, leaving .257" of empty space. Sounds excessive to me. Any and all input is appreciated. I'm not doing anything until I get a very good idea of what is safe. I plan on loading up about 20 rounds this weekend. Unless I get the knowledge I crave, I'll stick to the COL of 1.776 and the starting load of 21.0 gr. and start my workup. Thanks in advance.

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monstrosity_73
January 20, 2010, 10:20 PM
One other thing, Hornady recommends Win WLP primer. I have CCI's 300's and 350's. I'm thinking 350's due to the temps here during gun season.

Ifishsum
January 21, 2010, 12:29 AM
Is your barrel chambered for .44 mag or .445 supermag? You can't just use the longer brass if it's chambered for .44 magnum, are you planning to ream the chamber to .445 SM?

As far as I'm aware, empty space in the case isn't a big deal with smokeless powders. I use H110 (same as W296) in .357 mag and .41 mag, I know there is empty space in the case but I haven't measured how much, or ever worried about it. Even more so with Unique or Bullseye loads. I'm not aware of any maximum empty space, though some powders are position sensitive and may not ignite as consistently. I have not encountered this problem personally.

I would use the magnum (CCI 350) primers with W296/H110 powder. They do take a bit more to ignite than other powders according to most everything I've read.

monstrosity_73
January 21, 2010, 05:48 AM
I assume the barrel is chambered for .44 mag. I haven't checked the diameter of the chamber to the lands yet, but the max case length for the .445 is listed as 1.610. COL is 1.965. I'm looking at a COL for my finished product to be 2.045 or more possibly to get close to the lands. This may be totally unneccessary out of a pistol for a hunting round, but I'd like this thing to be as accurate as possible. Maybe I should just have it chambered for the .445, but I don't see that being cost effective in the long run. I'm taking a bullet to work today to throw on the comparator to check out. I'll take the barrel too and measure the chamber better. If air space isn't a problem, maybe I'll just seat the bullet out farther and see how it does for accuracy.

jcwit
January 21, 2010, 08:02 AM
I've read the title to this thread many, many times and I'm sorry I just have to say it. No offence ment to anyone, its just what I think of every time I read the title.

It all depends how far apart your ears are!!

Sorry couldn't help it.

Steve C
January 21, 2010, 11:07 AM
If I remember right I once read that W296/H110 needs a magnum primer and 80% or greater load density to reliably ignite.

Since you're shooting in a single shot the danger of setting off another round after a squib is minimal and would require some really neglegent action. Just load up a dozen rounds at the OAL you want to try and hit the range. If you get a squib you'll have to pound out the bullet from the barrel but so what, at least you know you'll have to up your charge or shorten your OAL. You can always pull the unfired rounds and reuse the components.

monstrosity_73
January 21, 2010, 04:41 PM
Thanks Steve,

I'm gonna take your advice. I measured the depth of a .455 gauge pin in my chamber today and it will not take the depth of the brass for a .445 supermag. I was just curious if it was possible. I feel confident enough now to start working up a load.

RidgwayCO
January 21, 2010, 04:49 PM
For .44 Magnum, even in a T/C Contender, don't worry about getting the bullet closer to the rifling. Go ahead and seat the bullet so that you can crimp in the bullet's cannelure, and use a pretty firm crimp. This crimp will give a little extra resistance for that slow-burning powder to push against as it starts burning. You're bullet's going to have a fairly long jump to the rifling in your Contender, but that's OK.

MichaelK
January 22, 2010, 08:17 PM
Hi M73

To help give you some information, I'm reposting some test results I put out a few months ago. Pay attention to the velocities of the 23.0 grain load for both lengths and the 23.5 grain load. As you can see from the data, increasing OAL by 0.1" results in a decrease in velocity, because the the same amount of powder in a bigger space results in lower pressure. However, what was a bit surprising to me is that only an increase of 0.5 grains to 23.5 brought velocity back almost to that of the control (1740 vs. 1744 fps). Using this as a benchmark, I would suggest you could increase your 296 charge by roughly 0.5 grains for each 0.1" increase in length. By the way, unless you have a chronograph to monitor whats going on, I wouldn't start this project yet. It's an excellent tool to let you know what's happening inside your gun when you make changes to a load.
Michael



I wanted to increase the performance of my .44 magnum rifle for short-range deer hunting with my 1894 Marlin. I determined that a 240 grain hollow-point could be seated out significantly further than the 1.610” OAL listed in manuals. I determined that a cartridge OAL of 1.850” just touched the rifling of my barrel, so I wanted to see how much extra performance I could get by seating bullets further out.

I first determined though that a 1.850” OAL would NOT feed through my action. The longest OAL that would feed reliably was 1.710” so I used that as my benchmark. I made some dummy rounds without a primer and filled them with water to determine internal volume. A OAL 1.610” cartridge had an internal volume of 1.52 grams (1.52 cc at 25C), while the OAL 1.710” volume was 1.74 cc, a 14.5% increase in volume. This extra volume suggests that I MIGHT be able to increase powder capacity by 14.5%. Assuming that 24.0 grains of H110 is maximum for a standard cartridge, I MIGHT go as high as 27.5 grains of H110 with a 1.710” OAL cartridge.

Since the cannelure of Remington bullets is positioned for 1.610” seating, a long bullet might recoil out of the brass during firing. I solved this by applying a second cannelure 0.120” below the factory one with a CH canneluring tool. My finished cartridges look like this.

http://i141.photobucket.com/albums/r55/kawalekm/1750length240grainbullet.jpg

I tested 5 rounds each at 23.0 to 27.0 grains of H110 at 1.710” and 23.0 grains of H110 at 1.610” as a control. I measured velocity at 10 feet, accuracy at 50 yards, and case head expansion. Here are my results.


Charge Velocity Group size Case head/change Comments

Control 1744 1.90” .458”/.000 factory load

23.0 gr. 1717 1.94” .458”/.000 1.5% velocity reduction

23.5 gr. 1740 2.04” .457”/-.001

24.0 gr. 1776 1.86” .458”/.000 Birth of our nation

24.5 gr. 1818 1.87” .459”/+.001

25.0 gr. 1825 2.23” .458”/.000

25.5 gr. 1864 1.51” .458”/.000

26.0 gr. 1887 1.87” .459”/+.001

26.5 gr. 1901 1.50” .459”/+.001 1920 ftlb KE

27.0 gr. 1949 1.35” .459”/+.001 Severe muzzle blast, too hot!
I expected a greater increase in velocity, but achieving 1900 fps was OK. Going by the rule that case head expansion should not be greater than .001 inch, it looks like even the maximum load I tested is OK. I didn’t see any really flat primers in this run, so I didn’t evaluate them. The 27.0 grain load FEELS too hot, judging from the muzzle blast and the level of recoil. It just felt like the right place to stop. From its level of performance, and good accuracy, I am considering the 26.5 grain load for future deer hunting.
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monstrosity_73
January 22, 2010, 10:29 PM
Michael,

That is exactly the kind of info I was looking for. However, I loaded 10 rounds using the factory cannelure and the BOL came out at 1.810 and I loaded them with 21.5 gr of the 296. Mainly because my first dump measured there perfectly and hornady suggests starting at 21. I just got my lee factory crimp die today and loaded 10 more, same charge, seated to 2.035, with a heavy crimp according to lee's instructions where there is no cannelure. Supposedly this will crimp anyway. I had wondered about working up a load as high as you did to fill more of the volume. I figured it out once, that to fill the case and have the oal where I wanted, I would have to load 28.9 gr with the VMD of 296 at .0656. I wasn't prepared to go that stout, as I don't have an extra .44 mag laying around and can't afford to replace any body parts. I don't have a chrony yet, so I was going to start light and work up until I can shoot a 1.5" group or less at 100yds from a rest. Once accuracy got any worse than that, I was going to back down to the accurate load. One other thing I'm thinking. Can I push this bullet to fast for optimizing expansion while passing through a deer broadside? Your response is greatly appreciated and I think it will be very helpful to me. Thank you very much.

MichaelK
January 23, 2010, 03:05 PM
Looking at Hornady's 7th manual, that load is way over max. Assuming that W296 and H110 are really the same powder, your max load with Hornady's 265 grain bullet is 22.2 to 23.2 grains. Looking at my own data, even lengthening your OAL will only let you put in a little more powder. I would very carefully increase your load density a half grain at a time, but I would suggest you get a chronograph. Midway was selling a delta Chrony for 85$ last month.

Another consideration is choosing a lighter bullet. I used my 26.5 grain load to take a deer this last season. The Remington 240 grain hollowpoint got 100% penetration so I didn't get a recovered bullet, but the exit hole was only slightly larger than the entrance, so I'd guess the bullet mushroomed without fragmenting. Can't argue much with meat in the freezer. That deer was dead 30 feet from the spot I shot it 60 yards away. Don't think you'll need more bullet than that unless you're after big, big game.
Good luck,
Michael

monstrosity_73
January 23, 2010, 07:54 PM
Ok Michael,

Chrony is on the way. Hornady estimates 1550 fps out of the contender with 23.2 gr of 296 pushing the 265 gr FP. I'm curious to see the difference in velocity from the FTX with it's magic tip. I already have 100 of these bullets, so I guess I'll see what they can do. Thanks again for the info and I'll post my final results.

Kernel
January 24, 2010, 12:00 PM
When you guys get time, you should experiment with some Lil'Gun powder. You may be able to get another 100+ fps, while maintaining safe pressures.

tdyoung58
January 24, 2010, 12:05 PM
unless you loading black powder empty space isn't a big issue since the flash / burn rate isn't nearly as quick in smokeless powders

Ol` Joe
January 24, 2010, 08:18 PM
Control 1744 1.90” .458”/.000 factory load

23.0 gr. 1717 1.94” .458”/.000 1.5% velocity reduction

23.5 gr. 1740 2.04” .457”/-.001

24.0 gr. 1776 1.86” .458”/.000 Birth of our nation

24.5 gr. 1818 1.87” .459”/+.001

25.0 gr. 1825 2.23” .458”/.000

25.5 gr. 1864 1.51” .458”/.000

26.0 gr. 1887 1.87” .459”/+.001

26.5 gr. 1901 1.50” .459”/+.001 1920 ftlb KE

I think you will find most books claim 0.0005" as max safe case head expansion, some say any measurable expansion is too much. Your 0.001" is double that recommended. These pressures too are in a handgun not a rifle where the casehead measurments are normally used.....just sayin`.

MichaelK
January 24, 2010, 10:37 PM
Actually, I should have deleted the case head numbers, because it turned out for a rimmed cartridge, what I was measuring was not really the case head. So, just ignore.

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