155gr Lee and the BO

[Boz330]

I've been fooling with my BO off and on now for a couple months. Finally got the Lee 7.62 mold and started with some of the powders I had on hand. The last time out 18gr of RL-7 shot a 6 inch group at a 100yd. 18.5 shot a 3+" group so thought that I was headed in the right direction. Loaded up some 18.8gr loads and thought that I would try some other powders. The 18.8 gr loads didn't improve as much as I was hoping for, but a load of 2230-S Accurate Arms powder printed into 1.25" X 1.62". I picked this powder up many years ago when I was shooting a lot of AR-15 for $50 an 8 pounder. I compared the Surplus with standard 2230 and there is a definite difference in granule size. Figures I find a good powder and I can't get anymore of it. I'll give it a try though.
I was surprised this powder shot that well since I hadn't seen it mentioned anywhere as a potential powder for this cartridge. Of course almost nothing is available anywhere so you have to use what you have.

Bob

[Moonie]

I like 15.0-15.5gr H110/W296 in mine with that boolit.

[Jupiter7]

I use lil gun, h110 &1680. As of now mine drop at 159.5grs, I run them over 15.5grs lil gun. I tumble lube and use aluminum gas checks. Cheap plinking and groups around 2.5". I worked up from 14grs for any readers, this was safe in my gun, work up please.

[Boz330]

I tried 110 and Lil gun in the same session but they weren't near as good. But I tend to try different stuff and then work with the stuff that shows initial promise. Those other powders might possibly do better with a little experimenting but I'm basically lazy and quit when I find something that works for me. If powder doesn't become available any time soon I might be working with a bunch of new stuff.

Bob

[Fishman]

For those that were wondering, like me, BO = 300 blackout.

I'm glad I figured it out because I've been wondering how the 155 Harris design would work.

[blikseme300]

Bob,

I dropped my charge of RL7 to 17.5gn and accuracy out to 100yrds improved from the 18gn I was using. I have tried slower powders than RL7 but even though they worked they were messy and accuracy was so-so. I have actually switched to a NOE 4-cavity .316-155 mold as my Lee was getting wore out after more than 2000 boolits. (I size to .310 and lube with Tac#1 in a Star.) The Blackout is a hoot to shoot and is a good hog hunting rifle here on the Rio Grande. My rifles are AR-15's with 16" barrels.

[Gunnut 45/454]

I run the Lee 155gr GC at.309" in my 300 BO with 15.5 gr of IMR4227 . Let my daughter shoot it this weekend and she shot 4 clay birds at 178 yards with 4 shots. With a good rest and proned out it will do just over an inch at 100 yards. This is my do everything bullet even my '06 Rem 7400 loves it!:-D

[Argentino]

For those that were wondering, like me, BO = 300 blackout.

I'm glad I figured it out because I've been wondering how the 155 Harris design would work.

Thank you for clarifying that ;-)

[Boz330]

I'm sure liking mine. The barrel that I ended up with is an 8 twist. I thought that I was getting a 10 twist when I ordered it but it took a while to get it and beggars can't be choosers. I think that I'm going to have to open up the gas port though. I don't know the size since I didn't assemble it. It takes a snoot load of powder to get reliable functioning though. From what I have read the consensus is that the Lee 155gr boolit is the way to go. Mine are water dropped WWs with a couple pounds of linotype added. They are running 17 to 18 hardness.

Bob

[nhrifle]

After I installed the barrel on mine, it wouldn't cycle anything but the stoutest charges. There were quite a few people bemoaning undersize gas ports so I figured that was the problem. I had a conversation with the owner of SI Defense (who made my barrel) and he told me they intentionally drill the port small so the end user can tune it as they want. After opening mine to .110", it runs like a top.

[Jupiter7]

I've been kickin' around the idea of an AR with either a 300BLK or 7.62 WT upper. I'm not interested in subsonic at all, and the Lee boolits along with NOE's .311-155FN are the projectiles I have in mind. The WT has more case capacity, and can be had with 1-12" twist, so intrigues me more than the shorter round.

I think the only thing that keeps 7.62x40 out of mainstream popularity is making brass and major manufacturer support. Forming brass is a little more involved vs 7.62x35.

[arjacobson]

I use lil gun, h110 &1680. As of now mine drop at 159.5grs, I run them over 15.5grs lil gun. I tumble lube and use aluminum gas checks. Cheap plinking and groups around 2.5". I worked up from 14grs for any readers, this was safe in my gun, work up please.

I use lil gun at 16 grs with lees 155. Works excellent with very good accuracy

[Jupiter7]

I actually got to chrono my 15.5 lil gun load a few days ago. I increased crimp before the range session. Only ran five at 1.988COAL through 10" barrel.

1. 1780fps
2. 1808
3. 1774
4. 1795
5. 1792

Had a sight in target at 100yds from bench. The crimp seemed to work well, 1.5" group and was able to hit 300yd 8.5"x11" steel a few times later in the session, 100 & 200yd steel all day long.