Ramshot Hunter, 280 Ackley Improved

What gives me pause is that last week, that load started to fall apart after 25 rounds. Slow three shot groups, with decent breaks but the last several rounds starting showing pressure. Sticky bolt lift and extractor marks.
Im curious how many times the brass has been reloaded prior to showing pressure signs?
 
I worked up a load with Hunter and 139 Barnes LRX.

-average 3,275 fps

- .720 MOA for five shots. Three shots at .510.

- SD was 9

This was going to be my go to load.

No pressure, good standard deviation, accurate. Plus, lots of energy out to 600 yards. The bullet, being all copper, should penetrate well. Additionally it's still hitting at around 2,300 fps at 600 yards. The ideal minimum for a Barnes bullet.

What gives me pause is that last week, that load started to fall apart after 25 rounds. Slow three shot groups, with decent breaks but the last several rounds starting showing pressure. Sticky bolt lift and extractor marks.

The ammo was exposed to the sun, so I figured that plus the chamber heating up, pushed the load too far.

So today, I slow things way down and keep the ammo out of the Sun. Still very accurate at 100 yards, but at 425, I'm getting like 8 inch groups. It's all vertical spread. So I throw the chrono on, my SD is 33.

***?

So I'm guessing that Hunter is extremely temp sensitive? Different temp today, hot chamber messes with the powder?

Also, I was shooting into a very minor headwind. Maybe the variation in the headwind could have caused that much variation?

Nonetheless, I just paid wayyyy too much for 5 pounds of IMR 7828 on gunbroker.

Can someone with more experience chime in? Do I ditch this powder? Is there something else I'm doing wrong?
Actually it's considered to be relatively stable.

Keeping your ammo out of the sun is important with any powder, it's just not something most folks think of.

There's a story of record long sniper kill where the guy intentionally put his ammo out in the sun to get max range out of it because the shot was so long. It worked.

The more we can do to keep things consistent the better off we were but ammo/powder temp is something very few of us really put any thought into in the field.

If you're hunting in extreme cold weather keeping your ammo in a shirt pocket close to your body and loading singles once the quarry is in sight can keep your ammo temp very close to what it was that cool spring/summer morning you worked up your loads instead of 30-50 degrees colder.

The same goes for PD hunting in the summer, keep it out of the sun and you can keep it 20-50 degrees cooler.

I live in a part of the country where you can kill a child by leaving them in a hot car in 30 minutes or cook at egg on the sidewalks in July/Aug even early September but where sub 20f highs are not at all unheard of in the winter so it's more of an issue for us than for folks living and hunting in milder climes where such violent temperature swings are not the norm.

We've had many years where there can be a 100 degree shift between summer highs and winter lows so for us it's a very real consideration.
 
**Update**


I cleaned the barrel with Hoppes copper cleaner….ran a soaked patch through 4-5 times. So much solvent was in there that it was draining out the magazine. I let that sit for 15 minutes.

I used a bore brush and and scrubbed for a couple minutes, focusing on the base of the barrel

Then I ran a snake through it 5/6 times.

Same load, just shot three rounds with an SD of 6 and an ES of 13. I'm still at the range and haven't measured the group but it looks pretty good through the scope.

Looks like it was a dirty nasty barrel.

Thanks for the help!!!
 
**Update**


I cleaned the barrel with Hoppes copper cleaner….ran a soaked patch through 4-5 times. So much solvent was in there that it was draining out the magazine. I let that sit for 15 minutes.

I used a bore brush and and scrubbed for a couple minutes, focusing on the base of the barrel

Then I ran a snake through it 5/6 times.

Same load, just shot three rounds with an SD of 6 and an ES of 13. I'm still at the range and haven't measured the group but it looks pretty good through the scope.

Looks like it was a dirty nasty barrel.

Thanks for the help!!!
You're still going to need to use a carbon specific solvent like Boretech Carbon eliminator to really deal with the carbon ring which is surely there. Hoppe's just doesn't get it.

If it's bad enough you'll need to alternate between the carbon specific solvent and something like JB bore paste because they are incredibly tough to remove.

At best our common solvents like Hoppes just gets what's loose and on the surface but once that carbon is really baked in just ahead of the chamber its a bugger to remove.
 
I ordered IOSSO paste on Amazon. That's what the thread previously posted about carbon rings mentioned. Is the boretech stuff better?
 
No pressure. Velocities were pretty constant. That group ended up being .586 center to center.

Seems like the rifle is back to where it was.
 
No pressure. Velocities were pretty constant. That group ended up being .586 center to center.

Seems like the rifle is back to where it was.
What about other groups, and how many times have you reloaded the brass?
 
Someone asked about the load.

It's 63 grains of Hunter and a 139 LRX.

COAL is right at usable mag length for me, which is around 3.4 inches.

Using a Hornady comparator, I'm 2.705 overall length.

Nosler brass, virgin, sized through a Redding die. FGMM 210 primer.

Rock Creek 24 inch tube with about 600 rounds through it. Ruger action.

It's slightly over the maximum load that Barnes publishes. Other that last range session, I have never had any pressure signs at all.
 
I shot three, three shot groups, they were all similar.

I took it out to 425 yards, and the groups spread out to roughly 6-7 inches (estimated), but I was shooting in wind. So I figure it's probably due to changed in the wind.

I measured ES on the second group and it opened up to 22 fps, which I attribute to a hot chamber.

The third group, I let the barrel cool quite about. SD and ES were similar to the first.
 
Rock Creek 24 inch tube with about 600 rounds through it. Ruger action.

It's slightly over the maximum load that Barnes publishes. Other that last range session, I have never had any pressure signs at all.
how many times have you reloaded the brass?
 

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