300 Blackout Chambering Issue

[xacex]

300 BO is not a tack driver, but you can get decent accuracy. With the 311410 with a gas check I can get under 2 MOA 5 shot groups at 100 yards benched, and under 4 without trying too hard for over 15 rounds. This is at almost 2200 FPS with a 130 grain H/P boolit. Still working on that load to see if I can get it down further. This is with ASBB tumble powder coating.

[petroid]

Well I guess either my mold just cast fatter than the rest or my chamber is tighter because even the naked dummy round was hitting the lands at 2.040 and with PC they aren't reliable past 2.010 so I can live with it. I'm not getting any feeding issues. Did have one that didn't chamber easily but it may have had a bit of a thick PC on it. shot 30 rounds this pm and that was the only hiccup. Accuracy wasn't terrible, 2" groups at 50 yards was the average. One group was sub 1" except for a flier which may have been the one that wouldn't chamber. Have to try that load out some more. I am getting a lot of soot with Reloader 7, not much with H110 and it seems to give better groups. I did shoot one group without gas checks and surprisingly it wasn't any worse than the others. I may just try skipping them and see how it goes.

I would like to extend a big THANK YOU to all who helped me through this issue. Hearing of your experiences with this boolit/cartridge and your advice has really helped me. I thought I was hosed but it looks like things will work out. Doesn't look like I have to buy another mold, this one will work for short to medium range plinking which is what I was looking for to begin with. I still have some final load development and chrono work to do, but it is feeding and chambering pretty reliably now. Thanks so much.


P.S. I would love to try a few boolits from the 311414 mold. Any chance I could purchase some from somebody to try out?

[popper]

Might try the 31-145C (150 gr) small nose for PC, PB. First try is 1720, 2" horiz string @ 50.

[xacex]

I cast up a batch of C312-155-2R from a 6 cavity mould this morning (ebay seller). The meplat is a little wider than the older 312-155-2R, but very workable in both of my chambers. I seated a dummy sized .311" and it chambered in my tighter chamber when seated to 2.060". At that length, the case mouth barely covers the lube groove.

I also cast up a few NOE 311414s. The NOE is .990" long vs the .930" of the Lee, but the NOE is lighter due to its narrower nose.The NOE is .303" ahead of the front driving band vs the .309" of the Lee just ahead of its crimp groove. .250" forward of those dimensions, the NOE is .301" vs .304" of the Lee. The NOE may work for those who want to PC it.

The last GCs I bought from Blammer were $23/K, which is much better than $32/K for Hornady. I see no difference between Gator Checks and Hornady other than the price, and I see no reason to not use GCs in that I want accuracy, and particularly with the stresses of the 1-8" twist and chamber pressure. 4" at 50 yards is pathetic, IMO, and not even acceptable to me at 100 yards. My cast loads are running 1.5-2moa with a dot or 2.5x prism sight.

Your attitude towards a new members effort is pathetic, and no one ever mentioned 4" groups at 50 yards. Keep that attitude over at 300blktalk where it belongs. This place is about helping people, and a safe place to ask questions without persecution.

Sorry OP, but the comment was unnecessary, and an opinion that didn't need to be vexed here.

[petroid]

Sounds like you are having all the same issues that I have worked through with the Lee 312-155 using both a CMMG and MAS barrel. First, filing down the ribs on the Pmag is definately needed to have good function with that boolit, especially after powder coating. It is a fat boolit to begin with, the powder coat just makes the ogive fatter. Second, make sure your sizing die is set to put the shoulder where it needs to be, I dont have the numbers in front of me right now, but if the shoulder is out too far you will have trouble chambering. Third, as Xaces said, that PC adds to the ogive, so you have to seat them deeper. The longer I make my rounds, the better results I have with my accuracy. Unfortunately, longer also means boolits are sticking. You should be able to cycle each round in and out by hand without having to mortar the rifle. Fix your mags, check your shoulder, seat those rounds short and I bet your issues will go away. Just remember that when you seat short, you will also increase pressure. Im memory serves, I think Im seating at 2.010.

Thanks for you help kyshooter. This is exactly what I had to do to get it to work

[petroid]

I don't feel that anyone was being rude, just relating their experiences. I appreciate all the advice and info that was offered up. My average is about 2" at 50 yards but I had one group that had four out of five in the same hole. There was one flier that was way off that I think was sticky to chamber and the round had to be ejected and rechambered

[fishhawk]

First off the way I read the post made by excess650 was that 4 inch groups were unacceptable to him at 50 yds and also is to me. He didn't attack or berate the OP he stated his requirements for his accuracy (4'' at 50 yds doesn't cut it for him) so I sugest that any one that has issue with his statement of his required accuracy reexamine what there own requirements are and move on with the members here. steve k

[petroid]

Might try the 31-145C (150 gr) small nose for PC, PB. First try is 1720, 2" horiz string @ 50.

The nose looks nice popper. Are you shooting from an AR? If so, how do they feed?

[petroid]

I cast up a batch of C312-155-2R from a 6 cavity mould this morning (ebay seller). The meplat is a little wider than the older 312-155-2R, but very workable in both of my chambers. I seated a dummy sized .311" and it chambered in my tighter chamber when seated to 2.060". At that length, the case mouth barely covers the lube groove.

I also cast up a few NOE 311414s. The NOE is .990" long vs the .930" of the Lee, but the NOE is lighter due to its narrower nose.The NOE is .303" ahead of the front driving band vs the .309" of the Lee just ahead of its crimp groove. .250" forward of those dimensions, the NOE is .301" vs .304" of the Lee. The NOE may work for those who want to PC it.

The last GCs I bought from Blammer were $23/K, which is much better than $32/K for Hornady. I see no difference between Gator Checks and Hornady other than the price, and I see no reason to not use GCs in that I want accuracy, and particularly with the stresses of the 1-8" twist and chamber pressure. 4" at 50 yards is pathetic, IMO, and not even acceptable to me at 100 yards. My cast loads are running 1.5-2moa with a dot or 2.5x prism sight.

That NOE mold may be the ticket! I'm gonna work with what I've got for now but I may heed to check it out eventually. Accuracy is improving just have to fine tune

[petroid]

Range Report!

The non gas checked boolits failed miserably today. At least with the load I tried. I shot WD COWW non GC boolits, AC COWW GC boolits, and WD COWW GC boolits. All over 14.6gr H110 at COL 2.010 and PC'd with HF red by dry tumble method. Non GC'd and GC'd WD boolits were horribly inaccurate. The AC COWW gave a 4" group at 100 yards. I chrono'd at 1767avg with SD 56 and ES 150ish. I dropped the charges from an auto disk measure and didn't weigh each one so that could explain the big SD or it could be the PC giving variable OAL which I didn't check on every round once I had the seating plug set. Either way, I'm sure there's some room for improvement with charge weigh and OAL variation but for a super cheap, reasonably accurate load that is suitable for short range plinking and hunting in the woods, I'm happy. I'm seriously thinking about using this load for woods deer hunting as long as I can verify acceptable terminal ballistics. Gonna have to drink more milk, LOL!

[KYShooter73]

I'm seriously thinking about using this load for woods deer hunting as long as I can verify acceptable terminal ballistics.

I will be using mine this year now that the kinks are worked out. I don't know what part of KY you are in, but around here in the hills a shot further than 200 yards would be very rare, which is perfect for the blackout.

[petroid]

I shot the new version of the Lee 155 over H110 today. 14.8, 15.3 and 15.8gr with 14.8 producing a 5 shot group covered with a dime at 50 yards! I had some 311414s over 19 and 19.5 AA2200 and the lighter charge shot a 5 shot group covered with a quarter. All of these were conventionally L&S .311" with GC.

I've got some more to test out and I got your package. Wow! can't wait to get to the range!

[petroid]

I will be using mine this year now that the kinks are worked out. I don't know what part of KY you are in, but around here in the hills a shot further than 200 yards would be very rare, which is perfect for the blackout.

I'm in Louisville and often hunt in Indiana and Western KY. My BLK is a pistol and legal in IN. Other places I'm in the woods mostly, anyway, so short range is the norm.

[petroid]

Went out this morning with some boolits from excess650. 311414 gave 1" at 50 yards and crayon of death about 1.5" much better than I expected. Those were grease boolits. I still have to PC the 311414s and try them out. Haven't got the SIL boolits loaded yet. Thanks a lot excess!