It cycles a 300 BLK AR just fine, burns extraordinarily clean, has 100 % case fill, and yields outstanding accuracy.
My accuracy load is 18.0 grains of N110 under a 125 Grain SMK and federal 205M primer.
(10" Noveske Barrel, Pistol Gas, 1:8 Twist, and TBAC 30P-1 Suppressor)
Last edited by Dr.Phil; 01-10-2014 at 11:08 AM.
What scope do you have on your BO, Dr. Phil? I have a 312 155 Lee mold. I intend to size it to.309, lube it with Rooster Red, and of course GC it. I will use either WC 820 or 4227. I want to load for about 1800 fps. I have read about 16.5 grs for H110 on this forum and that goes well with what I have learned with jacketed bullets. The only thing that I worry about is sizing down the 312 bullet to .309. I guess everyone is doing it, but I always heard that excessive sizing was harmful to accuracy. These are just my thoughts. What are others experiences?
I'm a competitive long range precision rifle shooter and tend to use more magnification than most for a given application.
Leupold has a Federal / Mil discount program that keeps me brand loyal. (I like good glass, but I'm cheap...)
3.5 power is low enough for me to have enough field of view for close in work and I either switch the scope out for my Tijicon Tripower or mount a Delta Point on top of the scope if I need a zero power aiming solution.
As for cast supersonic projectiles, I have not been brave enough to get into that yet.
My 300 BLK upper is setup for a full time suppressor and I did not want to risk a GC coming loose inside of it.
With powder coating becoming all the rage, I will likely try that out with a 175 grain cast boolit that is optimized for feeding in an AR.
That will give me an inexpensive supersonic plinking boolit that I can also use for 3 Gun and will make Major PF.
I have been fighting with my cast to chamber in my 300 BO. I thought my problem was the nose was too fat and it was jamming on the top of the Lands.
Cast sized to .311, brass formed from LC 5.56 MilSpec brass.
I just took some measurements on loaded rounds on the Neck.
Factory 300 AAC Blackout RP Brass - .331.
Cast .311 in a commercial case - .332/3.
Cast .311 in MilSpec 5.56 formed brass - .335.
.335 is just a little bit too large to chamber in the neck area. I am going to size some of my cast to .309 and start over.
More to follow I am sure.
Big Bore = 45+
With a Noveske Barrel, I size my 247 Grain NOE FN boolits to .309 and they are good to go.
The mould puts them out at .311 and I use a Lee sizing die to get them to .309
I have an old .308 die here that I am going to hone out to .309 and go from there.
Big Bore = 45+
That has been my experience. Notice that it is the thickness of the brass in some cases that causes this problem, exacerbated by oversized slugs..335 is just a little bit too large to chamber in the neck area.
Just have to tailor my cast to the brass - Which by the way is not uncommon when we deal with reformed brass that has been shortened.
I could just 'uniform' the necks and bring them down to SAAMI Standard- but when we are dealing with 2 to 3K of brass - I think it makes more sense to tailor the boolit size to the brass and spend more time shooting.
Now the above statement could change due to leading of the rifle, or problems developing in the gas system. Time will tell.
Time and weather permitting I have 3 different loads to test today with the RCBS 165-SIL and Accurate 1680. Initial test yesterday seemed promising.
Big Bore = 45+
Any of you ever try the 150 grain Saeco #316 flat nose in a 300 Blackout? Second from left in photo.
I like it for high production 30-30. Bullet is just the right length it drops into my Star size die leaving the base sticking up just enough to place a gas check. Flat nose doesn't dent the gas check on bullet below it. Plus Saeco makes it in a four cavity. Longer or pointy bullets I use my Lyman size machine at about one third the production rate. If it would feed it would be a good super sonic shooter.
First real test:
300 AAC BO, LC 2012 MilSpec formed cases
RCBS 165gr GC Sil bullet, actual weight = 175gr ready to load Lubed with Lyman Super Moly (Why? Because those are the ones I picked, I have some lubed with LBT Blue too!)
COL 2.200 (Yes I know it is short, but if I go longer the first driving band will jam into the rifling.)
50 yards benched
17.5 gr - 1.2 C to C with a 2 inch flyer at 12:00.
18.0 gr - 1.2 C to C lateral dispersion.
18.5 gr - 1.5 C to C with a 3 in flyer at 12:00
I need to load some more of the 17.5 and 18.0 and re-zero the scope and move to 100 yards. Both show promise to stay under 3 inch at 100 yards which is what I am looking for. Velocity doesn't matter as long as the rifle functions - but I will chronograph the loads to see what they are doing.
Big Bore = 45+
From the crimp grove to base it's .415". That places top of gas check just below a 308 case neck but grease is still in neck. However there is no front band above the crimp grove. It's .300" bore diameter. Thus in a 308 I'd set it out a bit and use no crimp in a bolt gun. In my 30-30 I seat them to the grove and use a light crimp. Total length of bullet is .880" with a .190" meplate.
I am getting ready to walk out the door for a weekend trip - how about we get together early next week and I will try to talk you out of about 50 of them so I can try them.
Might be a good choice for blaster ammo as it might be more accurate than my RCBS 165 SIL and even if it only matches it - the RCBS is a 2 banger - The Saeco is a 4 Cavity?
Big Bore = 45+
MGySgt: There will be no problem sizing that Lee 155 down to .309", and the GC will be on tighter, too. I shoot that boolit's sister, the 312-160, sized to .309" and get respectable accuracy. That said, it will probably shoot better at .311"-the problem, of course, is the chambering issues that can cause.The only thing that I worry about is sizing down the 312 bullet to .309. I guess everyone is doing it, but I always heard that excessive sizing was harmful to accuracy. These are just my thoughts. What are others experiences?
Personally I think Lil'Gun is the ideal 300 Blk supersonic load powder. Velocity is similar to H110, but with a lot less flash and blast. Anything faster than H110 is really too fast for maximum velocity with 110-125gr bullets.
I also use the Lee 155gr bullet. It shoots pretty well (I powder coat mine) and can be pushed to about the same velocity as a 125gr jacketed bullet.
The problem with the Lee 155, and most other cast bullets when used in AR15's, is the ogive diameter at the magazine rib. If they are seated to an optimum depth for the chamber, they feed poorly, and stack up in the magazine wrong. My P-Mags won't feed right with more than 15 of these loaded at once because of this issue. A long tapered nose is better for feeding in this round, but so far the only cast bullet I've seen with that kind of profile is the Lee 230gr, which of course is for subsonic use.
Flat nose should be better smack down for any hunting application. Have a big box of them here in BHN #9 alloy. I shoot those over 26 grains of Rx7 in the 30-30 Win 94 AE with 12 twist barrel. Never clocked them but they still hit in the front sight dot at 100 yards so they are over 2,000 fps. Iíll need to cast you up some hard ones for a fast twist barrel.
My mold is set up in a Magma one arm bandit casting machine. Then yes Saeco sells the four cavity that will run many per hour. Big production point is it will run through a Star size machine. Most rifle bullets actually do not very well.
If this flat nose will not run in a 300 Black out I donít know what FN would. Have been looking for a few years waiting to see this bullet show up in the 300 BO threads. Well dugh I guess weíll see. Iím no big 300 blackout fan but my son in law is all excited about getting one. Since he reads magazines. So I need a boolit. Lol
Weíll need to try the MP 180 HP also. And the lyman 311672.
Just for giggles. If thatís to much work on your schedule just say so.
Not looking to dump work on you.
Lee 309-170 feeds great for me.If this flat nose will not run in a 300 Black out I don’t know what FN would.
|BP||Bronze Point||IMR||Improved Military Rifle||PTD||Pointed|
|BR||Bench Rest||M||Magnum||RN||Round Nose|
|BT||Boat Tail||PL||Power-Lokt||SP||Soft Point|
|C||Compressed Charge||PR||Primer||SPCL||Soft Point "Core-Lokt"|
|HP||Hollow Point||PSPCL||Pointed Soft Point "Core Lokt"||C.O.L.||Cartridge Overall Length|
|PSP||Pointed Soft Point||Spz||Spitzer Point||SBT||Spitzer Boat Tail|
|LRN||Lead Round Nose||LWC||Lead Wad Cutter||LSWC||Lead Semi Wad Cutter|