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Re: Powder Coated Cast Bullet?

PostPosted: Wed Mar 15, 2017 7:43 am
by Colohunter
I'm definitely interested to see how they perform for you. I was shooting the 230 gr round nose bullets just because I have a mold for them from 45 ACP, so I had plenty of extras laying around. I think I even tried some 200gr SWCs. If you get yours to work I will have to look into another mold!

Edit to add the previous thread: http://450bushmaster.net/viewtopic.php?f=5&t=14209&p=45424#p45424
About 2/3 of the way down I have some pictures of the 200gr SWC bullets loaded. I don't think I ever took any of the 230gr RN bullets.

Re: Powder Coated Cast Bullet?

PostPosted: Wed Mar 15, 2017 10:14 am
by Hoot
engineer40 wrote:...snip...
Did Quickload happen to give you better powder options for cast bullets in this weight? Thanks!


I'm at work and don't have QL at my disposal. The additional weight will play in the direction of IMR4227. The bullet length difference will reduce the amount of case space used up when seated to produce the same COL, which in theory (see sig) will reduce the initial shot start pressure with the 4227. Unfortunately, there isn't a lot of powder choices between H110 and IMR4227 on the powder burn rate chart. Not having QL handy, I'm not sure whether the powder in between them has enough bulk to fill the case to say 80%, which starting loads of H110 struggle to acheive as well. I have tried whenever possible to never fill a case to less than 80% capacity with powder. I can see what W296 has for bulk when I get home and get my chores done. Brutal cold here, so not much else to do. It was -1 when I got up for work yesterday morning, but a balmy +9 this morning. Hoping for a warming trend this weekend. A week ago, it would have warmed up more than this coming weekend mainly due to the new snow cover that fell just before the temps did. Surface warming makes a big difference in comfort level, when its cold out.

Hoot

Re: Powder Coated Cast Bullet?

PostPosted: Wed Mar 15, 2017 11:24 am
by Al in Mi
1680 might be a good choice, used a bunch of it with cast heavies in the 454 years ago.

5744 might be another cast friendly powder, dunno if there is any data on it.

Re: Powder Coated Cast Bullet?

PostPosted: Wed Mar 15, 2017 7:33 pm
by plant_one
i think hoot is really onto something with the 4227.

and getting them to shoot is probably only a matter of finding the right speed.


once you PC - run them through a sizer, and of course make sure you flare your cases so you dont shave the PC off them.

Re: Powder Coated Cast Bullet?

PostPosted: Wed Mar 15, 2017 8:39 pm
by Hoot
With the additional weight and more importantly, shorter length (.920) start out with 34gr of IMR4227. The efficiency goes up as I expected with the additional weight. Work up in half grain increments and if QL is on the money, you should come into the sweet zone at 36gr or possibly a little higher. I have long ago gotten over the pain of pulling down loads and tossing the bullets though I don't strive for that. If I were approaching that experiment, I'd probably load up to 37 on the first iteration and watch for pressure signs as I walk the load up at the range.

Now for the bad news. I went back and reread your introduction post in the new members thread. The stock Bushmaster upper uses a carbine length gas system. It's not going to like slow heavy bullets creeping down the barrel. It may try to initiate the gas cycling action before they clear the muzzle and allow the pressure to drop, releasing the case from the chamber. Big, slow moving bullets were what led to the Corvette mod, to increase the bore dwell time. Watch for head swipes and distressed rims if you choose to shoot those heavyweights. That will be a sign that you should be moving to lighter, faster moving bullets and abandoning the juggernauts. IIRC, the dwell issue when using heavy bullets was more pronounced when running the 20" stock Bushmaster upper as it still used the same carbine length system and the bullets needed to travel 4 inches further before they broke the seal at the muzzle. I'm recounting this from memory, so take it as a best recollection. Others more familiar with the subject may wade in with reports from actual experience. I'm more of a lighter, faster guy in this caliber.

Hoot

Re: Powder Coated Cast Bullet?

PostPosted: Wed Mar 15, 2017 10:12 pm
by engineer40
Thanks for all of the suggestions guys!

Hoot, I'll definitely be looking out for signs of that when I do my testing. Could adding a heavy buffer and buffer spring increase the dwell time a bit without going to a rifle length gas system?

Thanks!

Re: Powder Coated Cast Bullet?

PostPosted: Thu Mar 16, 2017 5:13 am
by Hoot
engineer40 wrote:Thanks for all of the suggestions guys!

Hoot, I'll definitely be looking out for signs of that when I do my testing. Could adding a heavy buffer and buffer spring increase the dwell time a bit without going to a rifle length gas system?

Thanks!


No, we've been through that discussion years ago. The issue is where the gas sampling takes place in the barrel. Even those coiled up, extra length gas tubes don't buy you back the time you need. This caliber has lethality to spare regardless of bullet weight. I can tell you this with utmost sincerity. The perceived recoil of the heavier bullets is noticeably greater, even at the resultant slower speed, than the lighter bullets going faster. Namely because of the muzzle brake. It reduces the portion of the recoil impulse associated with the "rocket effect" when the bullet brakes seal with the muzzle but does next to nothing for the portion of the recoil impulse attributed to Newton's 3rd law. The portion is the directly proportional to projectile weight. A 200gr bullet launched to yield 2500fps is easily attained in the 450b. A 340gr bullet would need to slow down to ~1450fps to reduce its recoil impulse to the same level. Of course, not many people want to see how slow they can make their loads run now do they? The 200@2500 will produce a lot more "rocket effect" and that's where the brake comes into play. 200gr bullets slowed down slightly, say to 2200fps are real pussy cats to shoot by comparison. I always take some with me to the range in case another member there wants to try my rifle. I've had 10 year old's and significant other's say that they were not hard on the shoulder. The 200 traveling at 2200 has a higher TKO than a 30-06 shooting the same weight bullet. Just saying...

Hoot

Re: Powder Coated Cast Bullet?

PostPosted: Thu Mar 16, 2017 8:17 am
by engineer40
Hoot you bring up some very good points. I sincerely appreciate the time you've taken to respond to my posts.

Historically I've been loading 2 different bullets for my 450BM; the Hornady 240gr XTP Mag's and the Everglades 230gr JHP's. Maybe it'll be best if I keep these heavy cast bullets reserved for my TC Encore 460S&W Magnum rifle instead of trying to make my 450BM do something it wasn't intended to do ammo wise.

Half the reason I was going to try is honestly just for the fun of the experiment. I might donate a few pieces of brass to the idea still just to try it out. :D

Re: Powder Coated Cast Bullet?

PostPosted: Thu Mar 16, 2017 12:31 pm
by Hoot
engineer40 wrote:Hoot you bring up some very good points. I sincerely appreciate the time you've taken to respond to my posts.

Historically I've been loading 2 different bullets for my 450BM; the Hornady 240gr XTP Mag's and the Everglades 230gr JHP's. Maybe it'll be best if I keep these heavy cast bullets reserved for my TC Encore 460S&W Magnum rifle instead of trying to make my 450BM do something it wasn't intended to do ammo wise.

Half the reason I was going to try is honestly just for the fun of the experiment. I might donate a few pieces of brass to the idea still just to try it out. :D


Heck, half or more of the fun is experimenting with different concoctions. Don't ever stop turning over stones in search of something new. As far as that bullet not being right for the 540b, it is better stated that it may not be a good match for the Bushmaster factory barrel. There are aftermarket barrels available that will be a better match for them. See how this turns into a black hole for disposable income? ;)

Hoot

Re: Powder Coated Cast Bullet?

PostPosted: Sat Mar 18, 2017 10:16 am
by plant_one
Hoot wrote:Heck, half or more of the fun is experimenting with different concoctions. Don't ever stop turning over stones in search of something new. As far as that bullet not being right for the 540b, it is better stated that it may not be a good match for the Bushmaster factory barrel. There are aftermarket barrels available that will be a better match for them. See how this turns into a black hole for disposable income? ;)

Hoot


its called black rifle disease, and warning - its contagious! :mrgreen: :mrgreen:

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