Not sure what's going on but hopefully you guys might be able to help me trouble shoot. I had a load I was using last winter that started giving me some stiff bolt lift as the weather has warmed up. I my load was 46.5 2000MR in old Lake City match brass with a 190 smk 20 thou off the lands. Velocity is 2650 with a 20in barrel. I've got no indication of pressure as far as cratered/flat primers, loose pockets, or ejector swipe. My case necks are sooty which I found odd given the fairly stout load. Cases have been reloaded 9 times and annealed twice. I backed off the load to 46.0 and still have a somewhat intermittent heavy bolt lift. Rifle is an AI AW. Cases were neck sized once since being shoulder bumped. My initial thought is either I need to clean the chamber or the cases are getting work hardened. I have no idea how long this brass should last or if that is even a factor.
Intermittent Heavy Bolt Lift
- Thread starter Norseman1950
- Start date
Carbon ring? They can increase pressures.
How do the primers look? Not a end all, be all way to see pressure but it with other clues might tell you something.
Any moisture or solvent in the chamber?
You could try a set of small base dies to see if maybe the area just above the case head isn’t getting sized down.
How do the primers look? Not a end all, be all way to see pressure but it with other clues might tell you something.
Any moisture or solvent in the chamber?
You could try a set of small base dies to see if maybe the area just above the case head isn’t getting sized down.
I can go lower on the die. I didn't think of carbon ring but that's worth looking at. Primers look good. I was only shoulder bumping about .002 then neck size for two or three loads and repeat. Maybe should just stick with the shoulder bump with a full length die and see what happens.
Any tips on dealing with a carbon ring? Where does it form?
Any tips on dealing with a carbon ring? Where does it form?
Yeah... it's just a regular hornady die that I set up to bump the shoulder. I understand it's not reaching the web of the case the way I have it set.
Bore scope ordered... the amount of doo dads for this is never ending.
How are you bumping the shoulder without sizing the web? Are you talking like .002” versus FL sizing?
A 190 SMK @ 2650 FPS out of a 20" barrel, is it me or does that seem a little hot.
I haven't reloaded in awhile, but that's looking a bit warm to me. Especially when you consider that Federal GMM 168gr has the same advertised velocity. And, the Federal GMM 185gr Berger advertises 2600 fps and they bark pretty good coming out of my 24" barrel bolt gun.
A couple years ago I ran 168 SMK's with 2000-MR and at 47.5 gr and got 2679 fps. And yes, that was a hot load, but at a high accuracy node and and actually did pretty well.
When I run some numbers through QuickLoad, for the 190 SMK, the 46.5 gr is pretty hot, but if it's loaded close to the lands (which I was just guessing as to the COAL) it's probably running just a hair over SAAMI max pressure. I'd be VERY careful with this powder if this load is used in higher ambient temperatures (like 95°F +). If fact, I probably wouldn't, for safety's sake.
When I run some numbers through QuickLoad, for the 190 SMK, the 46.5 gr is pretty hot, but if it's loaded close to the lands (which I was just guessing as to the COAL) it's probably running just a hair over SAAMI max pressure. I'd be VERY careful with this powder if this load is used in higher ambient temperatures (like 95°F +). If fact, I probably wouldn't, for safety's sake.
I’m sure it is to an extent. I set the die up so it bumps the shoulder back .002 when measured against a fired case. I’m not bottoming the die out on the shell plate.
Seriously. Someone posted reloading data in one of the 6CM threads and when I ran their information through QL it looked conservatively north of 70kPSI. Dude acted indignant and said 'muh bolt lift is fiiiine'. The velocity race always yields the same results...it all works great until it doesn't.
FB the other day was 153gr Atip in a 6.5cm 26” barrel going 2950 as his “safe load” and he could go faster if he wanted.
Well, he seems to have matched my velocity with a 6.5 X 284 and a 29" barrel. He obviously shows some real potential for something. Maybe the Darwin award. That or he's just a troll.
If your way beyond Normal speeds ya gotta ask why.
Many use speeds as their pee pee for the contest.
PP 2000 is one of the most temp sensitive powder there is. I was running 47.3 with a juggernaut in the winter with no issues. First match in may that I shot I had to beat the bolt open with a hammer. That powder produces some amazing speeds but causes issues every time. Swap to Varget or 4895 and dont chase speed.
I get single digit SDs with Varget.
This is my 308 load using Varget out of a 20” Savage barrel. It also shoots sub MOA out to at least 600 yards.
This is my 308 load using Varget out of a 20” Savage barrel. It also shoots sub MOA out to at least 600 yards.
Hmmm??? It may not be the "most" sensitive, but it's not all that stable either . . . as I've had significant difference in my .308 using it in the triple digit temps of Arizona summers vs. mild spring temps like 70's. Powders like Varget, H4895 and AR-Comp (even IMR 4064) are more reliable in the AZ environment where there can be significant swings in temperatures from one week to the next.
Hmmm??? It may not be the "most" sensitive, but it's not all that stable either . . . as I've had significant difference in my .308 using it in the triple digit temps of Arizona summers vs. mild spring temps like 70's. Powders like Varget, H4895 and AR-Comp (even IMR 4064) are more reliable in the AZ environment where there can be significant swings in temperatures from one week to the next.
my test was at 30 deg and 130 using a 190smk well off the lands and 47 grains of 2000MR
if dude is loading close to the lands I can see how issues could arise
How far off the lands were you loading? I'm currently at 20 thou, not jammed by an any stretch.
I don't have a ton of experience with 2000mr but that's less variance per degree than the reloader 15 I've been chewing through for years.
I had problems like this. I ended up switching brass and it fixed my problem. Chamber was a bit tight.
Welp... found the problem. Brass needed to be full length resized. I bumped the shoulder 3 thou. No heavy bolt lift, easy extraction, life is good. Shot same load today around 70 degrees. Shoots very well. Primers look a touch flat. I suspect that if I add another 30 degrees to the equation with this powder It's going to be too hot. Time to put the neck sizer away for good.
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