fresh 300blk test fire question..... need some help

[Ron Padilla]

I got to test fire the 300 blk today and for the most part everything looked it good it was extracting at about 3:00 o'clock and we were working on trying to zero in the scope at the same time, and I know I have read somewhere the answer to this question, just don't recall the answer.  I was using 168gr amax with brass that I cut, formed and loaded myself.  when releasing the bolt it would not fully chamber the round at first I thought it was the magazine.  

 

I was using a magpul 40 round mag but only loaded with one round as I was going to clean between each round, so then we went to another 20 round magpul mag and the same thing occurred, with the 40 round the bolt would not lock back, with the other 2 magpul 20 round mags it would.  I also began to think that maybe it was the brass and maybe I did not prep it correctly?  Or is it something with the gun, when we would began to load and fire 2 then 3 and 4 rounds it would cycle fine, but still experienced the problem with it not wanting chamber the 1st round and thinking about it we were charging and releasing the bolt manually and it would not fully charge the 1st round.  as I mentioned this is a brand new fresh build from the ground up and the 1st for me, I have modified others but have not done a complete build.

 

I am sure that there is something that I am overlooking and there is a solution to the problem, just not sure where to look, if it seems that I have not explained something well let me know, I am trying to see this out in my mind the steps we were taking to go through the process today and don't think I left anything out, let me know what I am overlooking I sure I will hear from Dolomite and others on this, and thanks in advance.   

[173rdABN]

Are you bumping your shoulders back far enough when full length sizing your freshly made brass? I had that issue with my 300 whisper when I first started loading, and checking my shoulder bump fixed it up in a heart beat.

Also, for the bolt, what is your load data? Barrel length and twist? And have you chronod?

Also, try and not use the bolt release.... Use the charging handle to release the bolt by pulling it back all the way. The extra small amount of force could be all you need. Edited July 9, 2014 by 173rdABN

[Ron Padilla]

173rd I was just speaking with my son and I think that the failure to chamber was occurring using both methods when charging the fresh round in the chamber, what type of die are you using in your set up?  I understand what you are saying about adjusting the shoulder on the round, I just can t see it in my minds eye, if the die is adjusted according to mfg specs. I still have about 15 rounds of the new formed rounds and the one's from today that have now been fire formed to reload before our next outing hopefully in the next few days to try and chamber to see how it goes.  

[Dolomite_supafly]

I bet the bulelts themselves are not being seated deep enough and the throat is slowing things up.

 

The next problem could be your dies if they are Lee. There are some bad Lee dies out there.

 

BTW, do you reload for other calibers or is this your first?

 

I PM'd my number, give me a call and we will get this sorted out tonight. I will be up to about 11pm.

[Ron Padilla]

Got together with dolomite and I think I have a handle on the problem, I will be addressing the issue in the next few days when I load some more ammo, once done and test is completed I will get back and give a report.  thanks

[Ron Padilla]

well, I did say that I would report back after the few issues that I had with the fresh build I had with the 300blk.  Come to find out that I did not have the shoulder set back far enough Dolomite as well 173rd indicated that might be the problem, and that is exactly what the problem was, it take several frustrating hours to get the die set just right and several stuck pieces of brass as well.we did get er done.  The rifle shoots just fine I now have about 50 rounds down the pipe and painstakingly cleaning between each first few rounds then after a series of rounds.  The only thing to do now is make some upgrades as time and money allows before deer season, and figuring out where to find some lancer mags as the new G.I, issue and the new magpul that I have would not feed properly after the 1st few rounds so the saga continues.  see ya'll