Blown primers on 6.5 CM-Problem Solved on page 6!

After years of reloading with cheapest available brass, I've now adopted the best available approach. With the cost of all components going thru the roof, I will now only use the generally accepted best available. Not only do they last much longer, they have a consistent neck tension and primer seating force needed. Velocity and accuracy are enhanced.
 
pdog shooter said:
Please elaborate on "carbon ring"

Please elaborate on "carbon ring"

Found with search
new to me
thanks
Click to expand...
typically just ahead of the casing in the freebore you can get carbon buildup... the dreaded carbon ring. I just had to give my 7rum the what-for the other day because it wasn't just building a carbon ring, but a ring AND filling the first couple inches of rifling with heavy carbon. Took a good bit of soaking and a few hundred passes with an oversized bronze brush to cut the deposit out.
 
Definitely have to keep up with carbon removal. Sucks trying to get it out after its built up. I still haven't found anything that just dissolves it.
 
I bought a 3 piece cleaning rod and use the end section to put into a drill. I attach an oversized nylon brush with a cleaning patch and iosso or something similar. I don't spin it at high rpm's but it definitely works better than other methods I have tried.
 
bomberodevil said:
I'm doing some load development on a 6.5 CM Christensen Arms Mesa, with a 22" barrel. This rifle has approximately 300 rounds, and has been easy to develop loads for. I have developed loads for Nosler 140 AccuBond at 2734 fps with 41.2 grains of H4350, with 3-round groups at sub .400 moa, and SD of 6. I also have a load with Nosler 140 grain BT, 41.0 of H4350, .360 moa, an IMR 4350 load below .400 moa. All of these loads had zero pressure signs, and MV in the low to mid 2700 fps.

Today I try some load development with Hornady 143 ELD-X, H4350, Nosler brass, Federal 210 primers. I begin at 41.1 grains of powder, with intent of going to 41.8 in 0.10 increments, shooting for accuracy. Hodgdon site has 41.8 of H4350 as their max load.

At my first load at 41.1, I blow the primer. Thinking that was an fluke, I fire two more, both with blown primers. This is below my 140 grain AccuBond and BT loads that have zero pressure signs, and 0.7 grains below the Hodgdon site max loads. I pulled the rest of the loads and reloaded, starting at 40.3 grains of H4350. I can't believe that 41.1 grains of H4350 is over pressure. Any thoughts?
Click to expand...
I've been loading H4350 with ELD-X AND M's, and mine is shooting around the same FPS, and .20 . I did check the BTOJ and found that the stock ammo from Hornady is around 60 thou, off my lands, and it shot great sub .25 groups, my loads are better and are .035 off the lands, Those ELD-X do have a long BTOJ, so make sure to check them. Pressures will rise a bunch if your into the lands, as I'm sure you know.
 
bomberodevil said:
Good point. I forgot to mention, I take 8-10 measurements with the Hornady gauge and a fire-formed case from my rifle to measure the CBTO with every different bullet I use, and then start at .030" off the lands for hunting loads. I'll re-measure it this weekend, but my CBTO was 2.218", COAL at the lands was 2.876", and the COAL after backing out .030" was 2.846". I also trim every case to SAAMI prior to loading.
Click to expand...
I do the same thing with fire formed cases, and use the Hornady tool, and stock Hornady ammo in the 143 ELD-X measures about .0600 off, off my lands, because they are much longer on the Ogive, Been shooting mine around .030 off with great results, but heard many issues just like the one above with pressure.
 
Problem solved. Re-measured my CBTO and COAL, today's measurements were within .003" of last week's measurements. Still scratching my head on how this load was so much hotter than a couple of loads I've already developed with pretty much the same system.

Was looking through my notes page from last week, and there it was. I inadvertently added my .030" off the lands back into my math! I was on the lands! Stupid and sloppy math, my fault completely.

Double and triple check your math! Thanks to all who passed along great advice and tips.
 

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bomberodevil said:
Problem solved. Remeasured my CBTO and COAL, today's measurements were within .003" of last week's measurements. Still scratching my head on how this load was so much hotter than a couple of loads I've already developed with pretty much the same system.

Was looking through my notes page from last week, and there it was. I inadvertently added my .030" off the lands back into my math! I was on the lands! Stupid and sloppy math, my fault completely.

Double and triple check your math! Thanks to all who passed along great advice and tips.
Click to expand...
Good for you, what its all about
 
Lefty7mmstw said:
once you have your length, set up a pedro/dummy cartridge so you can simply screw your die down to it... works slick as snot if you are loading multiple loads with one set of dies
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I don't mind checking the headspace once in a while, I know it does shrink or erode over time. The dummy cartridge is a great idea too.
 

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