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View Full Version : Nose and meplat, justify your choice of the best type for AR rifles



Oldfeller
01-06-2020, 10:26 AM
This is a classical fresh bowl of popcorn discussion


Let's give out all the operating parameters so folks can try to not suggest stuff that simply does not apply to this contest.

Bullets will be cast of WW metal, air dropped and then powder coated with Eastwood Ford Light Blue powder. No tricks with the metal, no pure lead noses, nothing but a plain jane fresh from the WW cast slug.

Your nose types to pick between are truncated cone and round/flat both swinging a .250"-.260" meplat on a .3565" diameter slug.

The gun is an AR Legend 16" barrel at 1 in 16 twist rate, .3565" on sizing diameter (sized post powder coat of course).

Maximum length of bullet is .855" so bullet weights will be at most around 195 grains +~10~ grains depending on nose type picked.

Gun is magazine length limited and has relatively mild feeding issues for an AR based weapon. The throat length at .300" is matched to the magazine restrictions using CMMG 10 round magazines (a hunting magazine). This gun is non-SAMMI standard in the length of throat.

Throat is .3565" diameter at .300" deep from case mouth. It will load and unload (barely) a 3565" diameter powder coated slug. Throat is .3575 right at the mouth of the case so yes it is a tapered throat that will catch the sized bullets very nicely.

FPS velocity range is 1,700 - 2,000 fps. Expect no expansion, these are as-cast WW slugs -- the meplat does it for you if it gets done at all.

Effective rainbow range to consider is ~250~ yards, with most common range shots being well below 200 yards.

Your answer will balance out all of the above, and you must defend your ideas against other the other posters with their competing ideas.

You can cheat on this contest using whatever software programs you like, just explain the results in layman's English -- explaining what the programs are telling you. I despise answers that can only be understood by the 1-2 fans of a certain program, with the users intentionally withholding the interpretation of analysis results that can only be understood by the aficionados of that particular tool.



Reward for winning the contest:

Your ideas will be cut into a four banger mold and reality tested as the "Best cast bullet for the 350 Legend".

ole_270
01-06-2020, 10:42 AM
Just an example for information, I have no idea which type is best. I shot 3 does this year with Saeco #315 clone, Truncated Cone nose profile cast of an alloy approaching WW +1% tin,(1.4%Sn, 2.9%Sb), powder coated, at 2150-2200 fps. One was near broadside, one slightly turned from full facing, and one full facing. All three bullets exited, the one slightly turned exited the far flank, the full facing exited the rear of the ham. All had significant damage on entry, but I have no way of knowing if it was from the flat nose or if it started mushrooming. The two head on does traveled the furthest, about 60 yards, but they were fully aware of me and were alarmed before the shot. I need to get hidden better when sitting on the ground.
Edit to add; I would guess that the TC nose would feed better in the AR from a .35 cal bullet