I have been doing some pressure testing on some 300WM loads to get an idea of a starting point for my load development. I started at the smallest load recommended by Hodgdon and have been working up by 1/2 grain at a time. At each level I shot two rounds for better comparison. I noticed a very small set of ejector marks on one of the pieces of brass at the lowest load and every piece of brass has it on all higher loads. My bolt has two plunger ejectors and they are very sharp around their edges. The marks are very defined lines/circle from the edge of the ejectors. Other than that I can not see any signs of excessive pressure. The primes all look identical from 67gr to 70gr. No other strange marks on the brass and the bolt opens very easily all the way up to 70grs. Hodgdon says that a max load is 72gr. The ejector marks seem to be more noticeable at 69-70grs is this anything to worry about?
Plunger ejector marks on brass
- Thread starter JNG
- Start date
This is often cited as a sign of pressure that is too high.
However, my Remington 700 had a burr on the ejector and I used to get marks on my brass with all loads. It took it into the shop and had the ejector fixed up and the problem went away.
If you find that you're getting ejector marks with all loads, including factory, then you might need to get your ejector de-burred.
If it's only happening with reloads -- and even light reloads -- then I would start sizing your brass a little harder. It might be that the brass is sized a bit too big.
Try closing the bolt on empty sized brass. If that gives you ejector marks, then I'd get the ejector de-burred and size your brass a little tigher (this is what I did with my Remington, and it worked).
However, my Remington 700 had a burr on the ejector and I used to get marks on my brass with all loads. It took it into the shop and had the ejector fixed up and the problem went away.
If you find that you're getting ejector marks with all loads, including factory, then you might need to get your ejector de-burred.
If it's only happening with reloads -- and even light reloads -- then I would start sizing your brass a little harder. It might be that the brass is sized a bit too big.
Try closing the bolt on empty sized brass. If that gives you ejector marks, then I'd get the ejector de-burred and size your brass a little tigher (this is what I did with my Remington, and it worked).
- Location
- The Conservative part of Ontario
The belief is that brass flow indicates high pressure. Well, that's true, but then the 300 works with high pressure to begin with.
I'd be very carefull with my loads, and proceed, but I suggest you use more than two loads per increment.
Watch for the primers to be flattenned out and square shouldered in conjunction with the brass flow, and be very conscious of any increase in difficulty in lifting the bolt handle.
Also, you didn't say what brass you were using. It's possible that you may have some soft brass. Try Winchester brass, if you are not already using it.
I'd be very carefull with my loads, and proceed, but I suggest you use more than two loads per increment.
Watch for the primers to be flattenned out and square shouldered in conjunction with the brass flow, and be very conscious of any increase in difficulty in lifting the bolt handle.
Also, you didn't say what brass you were using. It's possible that you may have some soft brass. Try Winchester brass, if you are not already using it.
"...to get an idea of a starting point..." That'd be your manual.
I was told that 300WM works best when close to max pressure by my rifle builder. Hodgdon says start at 67gr and work up which I am doing. When I find my first signs of excess pressure I was told to back off 1 full grain and use that as my starting point. Say that point is 71gr. Then I load 5 @ 71gr, 5 @ 71.1gr, 5 @ 71.2gr, 5 @ 71.3gr...etc Eventually I will find the right amount to give me the tightest group possible. If I get to 71.5gr and I am not happy I can also go the other way starting @ 70.9gr.
The Brass I am using is Nosler Custom and the dual plungers do seem rather sharp around there edges...
Thanks for the feedback guys...
I was told that 300WM works best when close to max pressure by my rifle builder. Hodgdon says start at 67gr and work up which I am doing. When I find my first signs of excess pressure I was told to back off 1 full grain and use that as my starting point. Say that point is 71gr. Then I load 5 @ 71gr, 5 @ 71.1gr, 5 @ 71.2gr, 5 @ 71.3gr...etc Eventually I will find the right amount to give me the tightest group possible. If I get to 71.5gr and I am not happy I can also go the other way starting @ 70.9gr.
The Brass I am using is Nosler Custom and the dual plungers do seem rather sharp around there edges...
Thanks for the feedback guys...
shotgunjoe
CGN Regular
- Location
- winnipeg mb
What P17 said x 2.I also had a rem. rifle that didthesame thing.The spring in the ejector was so stiff that any contamination would cause it to stick and not retract all the way,it also had sharp edges.But when it was clean boy did the guy next to me swear about hot brass bounceingoff his forehead.
"But when it was clean boy did the guy next to me swear about hot brass bounceingoff his forehead."
The double plunger ejectors on my rilfle through the brass pretty forcefully. I guess I should make sure that no one I like is to my right...
The double plunger ejectors on my rilfle through the brass pretty forcefully. I guess I should make sure that no one I like is to my right...
You might be resizing too much. Mags should headspace on the bely, if your chamber is on the max side, you may have excess headspace. Try just neck sizing or only touching the shoulder. I marks disappear chamber is on max side and reload accordingly.
