SLOW Twists and FAST Casts Using CUSTOM Barrels...Results, Please?

[MBTcustom]

LUse the XCB rifle Lamar. You've got a 14 twist on that baby. The differance between 12 and 14 would be very negligible for the purpose of seeing how much % of engraving you get on a reactive bullet. You should be able to get long distance accuracy with the 30SIL at 2600-2700ish FPS without working up too much of a sweat. Will it hold out to 500 yards? Good question.
Recon you could toss a few into something soft and post a picture? I can run some through my rifling die (it's like a Lee PT die but made out of a piece of rifle barrel) and we could do a little long distance comparisons here. We could do a couple other bullets too? I've got the 311466, the XCB bullet, and a couple old Lyman designs you might have also.
Whatcha say?

[btroj]

Recovering rhem from snow is easy, just wait for the melt. Problem is know what each bullet was fired with! Is there a sure fire way to mark the bullets in a way that won't be destroyed?

[MBTcustom]

How about a post marking each snow "berm" with load data?

[oneokie]

Recovering rhem from snow is easy, just wait for the melt. Problem is know what each bullet was fired with! Is there a sure fire way to mark the bullets in a way that won't be destroyed?

Yes there is.



Find one of the micro stamping machines that several states were wanting to use on ammunition sold in their state.

[btroj]

Yes there is.



Find one of the micro stamping machines that several states were wanting to use on ammunition sold in their state.

Ah, ask Bloomberg. Anyone got his number?

Marking a snow drift with load data would work. Run probably has plenty of snow. Thankfully we don't.

[runfiverun]

I got snow.
I also have 50 other casters in my town of 2,000 people.
Good luck picking up brass here too, I even have to buy 9mm brass if I want any.

[btroj]

Make sure they don't shoot the same bullet as you? And keep them off your snow bank!

I don't know if we have 50 casters in our club of 2000 members. I hope not, they might start picking my berms. I know of a couple members of the club who are members here too so I have some competition.

[44man]

We had 1/2" of snow and fierce winds all night and today, -16 wind factor. The cold and wind should stop a boolit!

[btroj]

Go shoot a few groups and get back to us.

[Larry Gibson]

Friday I also tested the WQ'#2 alloy XCB over LeveRevolution powder in Dawn. I chose not to use a Dacron filler in the 30x60 like I used with success in the Palma rifle in .308W with 14" twist. It proved to be a bad choice as the internals sucked with the 5 test loads. I loaded 46 to 50 gr LvR in 1 gr increments to test. Even at 50 gr there was sufficient air space in the case for a Dacron filler. The velocity ES ranged from 58 to 116 fps and the psi ES ranged from 4,700 psi to 8,800 psi.....neither very good.

Accuracy with the first load of 46 gr wasn't all that bad at 1.85" for the 10 shots at 100 yards. After that the groups got larger and larger with some serious flyers.......as I mentioned in the previous post I'm finding that 2850 - 2950 fps seems to be the upper limit for #2 alloy. The problem I encounter here around between 2928 fps and 2972 fps was the bullets were shedding the GCs very quickly, like before the bullet got to the screens! I've had bullets occasionally shed a GC but the 47 - 50 gr loads did it quite consistently. If you look closely you can even see some of the stability indicators in the not round holes of the more extreme flyers.

The 46 gr load ran 2873 fps at 44,200 psi, 1.85".
The 47 gr load ran 2928 fps at 45,500 psi, 3.75".
The 48 gr load ran 2972 fps at 47,300 psi, 5.4".
The 49 gr load ran 3025 fps at 51,000 psi, 5.3".
The 50 gr load ran 3103 fps at 56,700 psi, 8.4".

Attachment 130856


Worse part of the bullets shedding the GCs was it really tore up the screens. Those little 3 gr GCs at 2900 - 3100 fps pack a wallop! Was the right flyer in the 49 gr load that took out the right diffuser. That's when I checked the screens and found all the damage. I'll be casting some 30 XCBs out of linotype and WQing them for further testing. Their BHN should be in the 28 - 30 range and perhaps the GC shedding will cease with the stronger alloy? If you note the 50 gr group at 3103 fps 4 of the shots that went to point of aim appear not to have shed their GCs. That is a sub 2 moa group and is what I'm shooting for (pun intended)

Larry Gibson

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[btroj]

How hard would it be to open the check shank just a smidgen? Losing checks is bad, destroying equipment is far worse.

[runfiverun]

Maybe annealing them would work too, it would avoid the uneven spring back rates of the two metals.
Thats why we swage up in size when forming bullets.

[btroj]

Hadn't thought of that but good point Run. Dang it man, you understand this stuff!

[geargnasher]

It takes a sudden and high force to bang an MTF bullet through the throat, my suspicion is the checks and bullet base are getting mangled in the neck, probably getting turned nearly inside out going throat entrance. That's what happens when shooting near-pure lead bullets at a certain point. I'm a little surprised that the tight-necked 30x60 (assuming same reamer as XCB?) is allowing this to happen, but I don't know what the neck clearance is in this setup, either.

One reason I detest the reverse-tapered check shank is that too much goes wrong when that much metal has to move to get the checks crimped on. Using a rebated check shank cures this, and the more pressure that's applied to the bullet base, the tighter the check fits, instead of the opposite.

Gear

[dtknowles]

Here is the Range report for some of the bullets Bjorn sent me.

http://castboolits.gunloads.com/show...00#post3139300

Tim

[44man]

I hate losing checks but also make mistakes. Made my 30-30 mold and have to tap checks on with a small hammer before sizing. Makes it tedious. I will lap the check area only with a brass lap if too loose.

[Cap'n Morgan]

As promised, a short description of a simple way to form cases by hydraulic pressure:

http://castboolits.gunloads.com/showthread.php?269029-Hydraulic-case-forming

Let's pray it doesn't turn it into a hydraulic vs. fire-forming thread

[Love Life]

Doesn't Hornady make hydraulic form dies?

[Larry Gibson]

Besides running a retest of the 30 XCB bullet over LvR shooting up the last of my cast #2 alloy cast ones I decided to try a couple different bullets of different alloy. Some discussion has been given to the use of the 30 XCB and 30x60 XCB cartridges for hunting. Much discussion has also revolved around the use of a different alloy for hunting purposes.

Well I just happened to have some 150 gr Accurate XCB bullets that were HP'd by goodsteel. They were cast of 50-50 alloy (COWWs = lead), WQ'd and allowed to age some 2 -3+ months. These were sized at .311 with Hornady GCs installed and were lubed with 2500+. No effort was made to weight sort but a good visual inspection rejected some from use. I chose to use IMR4895 with a Dacron filler as that was what was used with the LBT 150 gr bullet and thought it would make for a decent comparison given the bullets almost identical weight. Those were cast of WQ'd #2 alloy and even though used for fire forming cases gave excellent performance (1.6") up through 2800+ fps. I loaded 37 through 42 gr and used a Dacron filler.

From the pictured results you can see the Accurate XCB bullets performed quite well in the 16" twist of Dawn. The 37 - 41 gr loads all were under 2 moa. The 41 gr load began to evidence some problems with some of the holes showing slight bullet tipping and appeared to having crossed the RPM threshold for that bullet/load combination. The 42 gr load confirmed it was indeed over the RPM threshold as the group opened to 3.4" None the less the 40 gr load may be a very good and useable load for hunting to 400 yards IF the expansion of the load remains linear as the range increases. Still though the 30 XCB of 50-50 alloy did not hold up as well as the LBT 150 cast of #2 alloy.

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Additionally I had some 311041s from a Lee GB mould cast of COWWs + 2% tin and then mixed 50-50 with lead; my usual alloy for hunting .30 caliber cast bullets. These were AC'd and were cast probably 6 - 8 months ago so they were well aged. They weighed right at 170 gr and were sized .311 with Hornady GCs applied. Again no weight sorting was done with only a cursory visual inspection being done. BHN on these bullets is 14 - 15. These were lubed with my own 50/50 alox/beeswax lube using alox 666. These were loaded over 49 - 54 gr of H4831SC with 54 gr being 100% loading density as with these pretty soft bullets I wanted a "slow push".

To say I was mildly surprised and very pleased with the accuracy and velocity in the 16" twist barrel of Dawn would be an under statement! These bullets are hard pressed to do this well at 2200 fps out of my '06s with the same slow burning powders. The 53 gr load gave a muzzle velocity of close to 2700 fps with sub 2 moa accuracy! If that holds at longer ranges I would consider this to be an excellent load for deer and pig hunting to 300 yards where the remaining velocity would still be about 1600 fps with 1000 ft/lbs of energy. For hunting from a stand the longer barrel would not be a hindrance at all.

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Seems the XCB cartridges just may be a lot more "versatile" than some may think.

Larry Gibson

[btroj]

But it still isn't a 30 BR......