Best cast bullet mold for 350 Legend in an AR?

[rickt300]

Well the pins are a learning experience. The mold likes "HOT" lead and I need to clean it again and polish the pins again. However I got it to start making perfect bullets. As for function in my AR After I figured out seating depth which is just in front of the crimp groove making for a pretty short overall length I could count on seven feed fire and extracts in a row and very good accuracy. 7 is all I load in the 10 round magazine. Problems I had were directly related to the 145 grain factory loads rough handling of the brass which must be smoothed with fine sand paper. What a crap factory load. My final load is 21.7 grains of I4227. Sized to .356 after powder coating with the gas check I found all went smoother if I rolled the bullets on my lube pad. I used Harbor Freight Red and it added .006 to outside diameter! However it took being sized from .366 to .356 in stride. Going to order some different powder.

[rickt300]

Ok I got around to testing some of the LEE 35-200 bullet. Seated as far forward on the bullet as there is a full diameter, same powder charge as above, powder coated with the crap Harbor Freight red, gas checked and my lead mix is just enough wheel weight material to get almost pure lead to fill out the mold (around 1/3 of total). Function is slick and accuracy very good. Leading non existent. Probably going to use this bullet for the spring feral hog and crappie fishing expedition. One of the things I learned about getting the Legend to feed, short bullets do not support the case wall where the case hits the bottom of the chamber allowing a dent which sometimes stops the round from fully seating and chambering. I think before long I will do some more work on the feed ramps carefully lowering it some to somewhat slightly straighten out the trip into the chamber.

[P Flados]

... work on the feed ramps carefully lowering it some to somewhat slightly straighten out the trip into the chamber.

Be careful about removing material at the back of the chamber. You really want the case walls to be fully supported.

And cases can have different web heights.

On an AR it is tough to figure out how far forward the feed ramp can extend.

This is an area where better specs on the SAAMI drawing would have been helpful (i.e. min case web height and max distance from bolt face to end of feed ramp).

[rickt300]

The AR feed ramp is separated from the chamber by around .3 or so, you can alter the heck out of them and not touch the chamber. It appears BCA used 300 Whisper/Blackout feed ramps for the 350 Legend. In my opinion a mistake which causes the bullet to hit the chamber a bit high.

[ElCheapo]

I've been getting good performance out of the LEE 200 grain RFGC as well. I purchased a BC side cocking upper and a batch of Starline 350 Legend brass. So far accuracy with the LEE has been great. I've only shot them to 50 yards, but PC'd and goosed along with a healthy dose of AA#1680 they seem to stack right on top of one another. This is without the gas check and running right at 2000 fps. I'm hoping to get 2200 fps with no leading. Just need time to get to the range and try a little more powder. So far so good, no pressure signs and the gun feeds and ejects perfectly.

[ElCheapo]

I was able to get to the range and test my loads. 2200+ fps with no leading out of an 18" BCA upper at 35 degrees F. No pressure signs and nice tight groups too, and this without the gas check. As temps climb I can drop the powder charge to keep the same velocity or just use gas checks. This bullet really performs nicely in the AR15! Feeding, function and accuracy are all great, and at this velocity it surpasses the 35 Remington factory load. Now I just need a big boar to test it on!

[cwlongshot]

I wasn't able to get much past 2000 with a 200 grain bullet before expanded case heads and blown primers, in an AR. I can do it easily with a Ruger, American bolt action, but I know I'm surpassing 55K and pressure.

[ElCheapo]

I wasn't able to get much past 2000 with a 200 grain bullet before expanded case heads and blown primers, in an AR. I can do it easily with a Ruger, American bolt action, but I know I'm surpassing 55K and pressure.

AA#1680 gives low pressures in the Legend and allows the careful handloader to assemble more powerful loads. I don't think there's a better heavy bullet powder for this caliber.

[Beaverhunter2]

I'm using AA1680 in the 350L as well. I was running a Lee 200 RCBS clone. I just picked up the MP 360-200 (also RCBS clone). I'm getting 1940fps with 27.0gr. out of an 18" AR. When I water tested at 125yd velocity I only got slightly above caliber riveting. I'm now trying to find out which HP pins I want to use. So far my rifle seems to prefer the deep HP but more testing to do. The mold is a work of art and throws the most consistent boolits I've ever seen. I keep 90% and sort to 0.1 grain with half in one pile and half in the other.

John