So I just got home from my elk hunt. I used a 300 wsm I put together myself. I'm shooting 195 gr badlands right at 2900 fps, using staball 6.5. It shoots great. Not to get to deep into hunt details but I ended up firing 4 times. I was getting some heavy bolt lift on the first three shots, The fourth shot, I couldn't open the bolt, thank god that was the kill shot. I had a few pieces of brass when doing load development I could not get sized properly for whatever reason. I tossed those out. All other brass chambered fine. Would going from 800 feet to 8700 feet change pressure? I totally understand the elevation drop, but never thought about pressure. I was shooting high at a long distance
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Will elevation affect pressure
- Thread starter Jpron
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RegionRat
Well-Known Member
Internal ballistics and external ballistics have only a small overlap due to climate.
The temperature is the more important parameter that affects velocity, the Density Altitude affects the trajectory.
In so many words, a load that was stable at a given temperature at sea level, doesn't tip over in terms of pressure by going to altitude. Going very cold or hot can be another story.
The temperature can have a strong effect on some powders. Most powders will slow down at cold but there have been a few with a weird behavior that speed up. If there is any excess cleaner or lubricant in the barrel, or a carbon build up, you can expect trouble when cold as well.
In most cases, going much hotter will cause this, and I don't recall Staball being as bad as some other ball powders.
Any chance there was oil in the barrel? Dust, snow, mud?
The temperature is the more important parameter that affects velocity, the Density Altitude affects the trajectory.
In so many words, a load that was stable at a given temperature at sea level, doesn't tip over in terms of pressure by going to altitude. Going very cold or hot can be another story.
The temperature can have a strong effect on some powders. Most powders will slow down at cold but there have been a few with a weird behavior that speed up. If there is any excess cleaner or lubricant in the barrel, or a carbon build up, you can expect trouble when cold as well.
In most cases, going much hotter will cause this, and I don't recall Staball being as bad as some other ball powders.
Any chance there was oil in the barrel? Dust, snow, mud?
RegionRat
Well-Known Member
Just a suggestion, even though it may or may not have had anything to do with your pressure issue.
I run a piece of electrical tape on the muzzle when hunting elk/deer.
I have seen many accidents, and have cleaned out too many plugged barrels. I have converted many of those folks to tape on the muzzle when hunting in the Rockies.
I run a piece of electrical tape on the muzzle when hunting elk/deer.
I have seen many accidents, and have cleaned out too many plugged barrels. I have converted many of those folks to tape on the muzzle when hunting in the Rockies.
The Oregonian
Well-Known Member
How long ago did you load the ammo?
I ask bc cold welding can happen and increase pressures. If you loaded the rounds recently then cold welding is not likely the issue.
I ask bc cold welding can happen and increase pressures. If you loaded the rounds recently then cold welding is not likely the issue.
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PddPdd
Well-Known Member
black finger cots work well for covering muzzle and/or brakes and stay on well.
Available on amazon.
Available on amazon.
RegionRat
Well-Known Member
@The Oregonian raised an important point.
If the necks were very clean, and there was no attempt to add anything to the necks, it is possible to get erratic performance if there is adhesion between the bullet and the brass. Time also plays a factor.
If the necks were very clean, and there was no attempt to add anything to the necks, it is possible to get erratic performance if there is adhesion between the bullet and the brass. Time also plays a factor.
I have had damp brass cold weld. Almost blew up my 6mm creed, got a few flurry's of snow in the ammo box when I went to load the gun. Must have welded the bullet to the case.
Month ago
Was your gun or ammo wet when you shot 4 x ?
No.
Betting that it's more to do with the wet cases than bullet weld. Always spritz water on your cases and check for pressure before settling on that as your load. Wet cases wreak havoc on warm loads.
I had a wet case take me for a loop, was verifying POI in the rain with a hot load, very stiff bolt lift almost locked up the bolt, lesson learned.. when working up loads take @parshal advise "Always spritz water on your cases and check for pressure before settling on that as your load"
