So I had 130 once fired Lapua brass from my .260 to resize last night, and 30 of them would not fit into my shell holder in my press,they were to wide and would actually start to peel brass off if I tried to force them.All of these were run through the sizing die when they were new and they fit fine.These cases were used for load testing so a few of them were hot loads; I had a sticky bolt lift a few times, but nothing terrible.Any one experience this before?I am hoping that I haven't wrecked 30 pieces of Lapua brass!
Problem with .260 Lapua brass
- Thread starter johny2sticks
- Start date
Normal chamber pressure and a cartridge firing below, red and yellow areas are high stress stretching areas.
Exaggerated over pressure and brass flow of a cartridge case below, expansion in the base web area is a sure sign of over pressure. Another pressure sign is brass flowing into the ejector button on the bolt face. Dotted lines show "WHY" the cases does not fit in the shell holder.
Sometime when I fireform brass I jamb the bullets hard into the rifling, "BUT" I do this at reduced loadings to reduce the pressure. In simple English your loads may have looked more than safe on paper but your bullets may have been seated too close to the lands and caused a pressure spike.
Below as an example firing 5.56 NATO ammunition in a .223 with a older type short throat.
Below pressure signs on a AR15 rifle, please note the brass flowing into the ejector button area. The smearing marks or "swipes" are caused by the wrong gas port pressure (over gassing) and the bolt rotating "before" the cartridge case looses its grip from the chamber walls.
Barrel Fouling and Pressure
http://bulletin.accurateshooter.com/2007/09/barrel-fouling-and-pressure/
New button rifled barrel at throat and two inches from muzzle.
Exaggerated over pressure and brass flow of a cartridge case below, expansion in the base web area is a sure sign of over pressure. Another pressure sign is brass flowing into the ejector button on the bolt face. Dotted lines show "WHY" the cases does not fit in the shell holder.
Sometime when I fireform brass I jamb the bullets hard into the rifling, "BUT" I do this at reduced loadings to reduce the pressure. In simple English your loads may have looked more than safe on paper but your bullets may have been seated too close to the lands and caused a pressure spike.
Below as an example firing 5.56 NATO ammunition in a .223 with a older type short throat.
Below pressure signs on a AR15 rifle, please note the brass flowing into the ejector button area. The smearing marks or "swipes" are caused by the wrong gas port pressure (over gassing) and the bolt rotating "before" the cartridge case looses its grip from the chamber walls.
Barrel Fouling and Pressure
http://bulletin.accurateshooter.com/2007/09/barrel-fouling-and-pressure/
New button rifled barrel at throat and two inches from muzzle.
Last edited:
paperslayer
Regular
- Location
- Chilliwack
factory chamber or custom?
anyway, they are likely done. Primers probably won't be tight even if you can resize
anyway, they are likely done. Primers probably won't be tight even if you can resize
Thanks for the replys everybody.It is a custom chamber,and I just went and looked at all the cases that won't fit and they all have a little round mark on them on the outside bottem of the cases.Some of the ones that fit have it as well,I guess I got lucky with those ones.Lesson learned,sucks that I ruined good brass though!! The last loads I shot were 44 grains of H 4350, 139 gr. Lapua Scenars and CCI BR2 primers seated .005 off the lands. Had sticky bolt lift with that load(but grouped awesome) so I backed the load down to 43.6 grains,but have not fired them yet.I am hopping this brass was from some that I had loaded up to 44.5 grains and fired while back home on holidays in Penticton last summer;it was over 30 degrees out that day so maybe that is where the "way to hot" happened.
I dont want to jack this thread but iv had what i thought was a weird problem and it sounds like it could be overpressure too.
Iv been using a load of 25.3 gr varget with 80 amaxs in my .223 for a while no signs of over pressure that I could see, then when I got a Forster Benchrest seating die I noticed that the brass wasn't going into the sleeve all the way on all the cases giving me inconsistent seating depth, its like the web of the case is slightly expanded. some cases were worse than others (about 10 thou), I tried full length resizing and that didn't help but a piece of new brass seemed to work fine.
its lapua brass
any thoughts?
Iv been using a load of 25.3 gr varget with 80 amaxs in my .223 for a while no signs of over pressure that I could see, then when I got a Forster Benchrest seating die I noticed that the brass wasn't going into the sleeve all the way on all the cases giving me inconsistent seating depth, its like the web of the case is slightly expanded. some cases were worse than others (about 10 thou), I tried full length resizing and that didn't help but a piece of new brass seemed to work fine.
its lapua brass
any thoughts?
measure the solid portion of the base of the brass, compare a new piece of brass and your fired brass, if the brass is swelling then you may have early pressure signs, they may bulge before the primer and bolt lift tell you that you have high pressure..
In aheppners case we would need to know if it is a factory chamber or a custom chamber........it could be a out of spec factory chamber and it may be time to full length size the brass rather then neck size.....if you already have full length sized then check and make sure that your using a small base full length sizing die....also how many times has it been reloaded? If they are hot loads then 5-6 times could possably be the expected usage life
In aheppners case we would need to know if it is a factory chamber or a custom chamber........it could be a out of spec factory chamber and it may be time to full length size the brass rather then neck size.....if you already have full length sized then check and make sure that your using a small base full length sizing die....also how many times has it been reloaded? If they are hot loads then 5-6 times could possably be the expected usage life
Agree
Rather than jumping to the dreaded over pressure conclusion, let's do some trouble shooting first........try to seat a primer. If it falls in as I suspect it may then you have overmaxed your brass. However I had a shell holder and a bunch of Norma 7mm RM once upon a time, that had not been over pressured at all, but would not go on the RCBS shell holder. I went down to my local reloading supply store and found a Lyman X13 that fit them and used that brass for years after that and have used that old X13 in a few other instances. I don't know about Lapua but I have come across brass with a shallower than normal extractor groove cut, which after the first firing would not go on the shell holder but again had not been over pressured. I then took one of my #3 holders and chucked it in the lathe and removed about 10 thou from the lips, opening up the holder. This has been a very useful shell holder after that, in a lot of ways.
It's worth looking into in case you just have a min/max problem, as opposed to a ruined lot of Lapua brass.
It's worth looking into in case you just have a min/max problem, as opposed to a ruined lot of Lapua brass.
X2
Yep. I load 42.5 gr of h4350 and I don't push it much harder. 43.5 gr seemed a little too stout for me.
These are all with my 139 scenars as well.
