Generally speaking does accuracy tail off after several reloads with the same brass. Im on my 11th reload with one of my batches and accuracy seems to be tailing off. It's a 308 with approx 600-700 rounds fired in total. I haven't changed my reloading habits and the brass is in good shape with the exception of thinning neck walls and slightly loose primer pockets. Annealed once after 6th firing.
Used brass accuracy degradation?
- Thread starter MHouser
- Start date
- Location
- Ottawa origanally Muskoka
If you aneal the brass no. Best resaults can be had by anealing after every reload.
If the necks are thinning then there may be some changes in your loads due to this...a thin neck won't crimp as tight, it will have more play in the chamber, may have increased bullet run out, won't size the same....
If the necks are thinning then there may be some changes in your loads due to this...a thin neck won't crimp as tight, it will have more play in the chamber, may have increased bullet run out, won't size the same....
gunrunner8
CGN Ultra frequent flyer
- Location
- Kamloops, B.C.
The throat in your rifle might be longer as much as .015" or more so IMHO it's time to seat those bullets for longer COAL....
Pudelpointer
CGN frequent flyer
- Location
- Lethbridge, Alberta
Neck tension is likely changing/variable due to the thin necks, resulting in erratic pressures and corresponding velocities.
JMO
JMO
I'm thinking the BR crowd have not experienced that problem. I'm too lazy to beat through my library to quote how few cases some national champions used to last a full season, but their cases got loaded more than 11 times!! And no, they did not anneal every time either. Like, I can't recall the author referenceing annealing, and since they reload between stages, at the range, for sure it wasn't every time they reloaded!
I only neck size, and the brass is not worked that much at all, thus the ability to reload many times. For true consistency should i not be retiring brass after one or two firings as I would think that the potential for inconsistency is magnified each time i reload the same brass. Small errors on top of small errors result in much greater errors.
I measure everything that's possible to measure and cant really account for the decline in accuracy.
I feel like if I toss this lot of brass and start over that I will be back around the .6 moa mark instead of .9 where I am now.
Most folks say that fired brass is better since it is "fire-formed" for your specific chamber. My thought on this is 100% true. A lot less movement during firing. Assuming you size only the necks when you reload. Maybe 11 firings is the end, though. Don't know - I try to keep several weighed lots of over 1000 cartridges each, so I ran over 10k through one particularly happy barrel, and almost 4k on the factory barrel before that and I just started cycle #5 on the brass.
But....there's a point where it needs some restoration and TLC.
My best 308 brass gets a bit of a "donut" around the inside the base of the neck after 4 firings. Inside neck reaming (before sizing) or uniforming with a mandrel and then neck turning the outside makes it all uniform again. Then trim it up to length.
Get a piece of your fired brass - before you resize. drop a bullet into it. If it drops right down inside - no donut. If it drops smoothly in and then hangs up - you have a donut. This is from brass flowing around during firing. If you're loading out long, this probably won't affect you - but if you're seating deep, back into this "donut" then the donut will force outward and make a bulge in the outside of the neck. That can cause chambering problems, or worse.
After LOTS of firing, the brass near the head of the casing is probably getting thin (that's where the excess brass forming the donut is coming from). So it's worthwhile to hacksaw a casing down the middle every once in a while to see how your "pile" is progressing.
The act of sizing brass makes it more brittle and moves brass around as well. (bend a coathanger enough and it eventually breaks -- same principle. The forming is probably more harmful than the heat of firing...) I think annealling the case mouths reduces these tendencies - but it seems like a lot of work so I can't be bothered.
Ideal situation (IMO) would be to use once fired brass from your own chamber -- size necks only with collett die. Use shoulder bump die to knock them back a bit if they start to get tough to chamber after 5 firings or so. Neck turn at the start ONLY if neck thickness variation is garbage (a lot of work) And then uniform from teh inside with a mandrel and neck turn right down to the shoulder after 4 firings or so ONLY ENOUGH to clear that "donut" out of the way. Or run a reamer through before resizing every once in a while to do the same thing.
Do you have a ball micrometer? - what's your neck wall thickness - more importantly, how consistent is the thickness. Possible that you have minimal runout becasue a straight die is keeping things straight -- btu there could be some heinous neck tension things going on. Also - seriously check (by cutting and visual inspection) the case wall down near the head of a few samples. Accuracy aside, I'm curious if you're on the road to a head separation...
But....there's a point where it needs some restoration and TLC.
My best 308 brass gets a bit of a "donut" around the inside the base of the neck after 4 firings. Inside neck reaming (before sizing) or uniforming with a mandrel and then neck turning the outside makes it all uniform again. Then trim it up to length.
Get a piece of your fired brass - before you resize. drop a bullet into it. If it drops right down inside - no donut. If it drops smoothly in and then hangs up - you have a donut. This is from brass flowing around during firing. If you're loading out long, this probably won't affect you - but if you're seating deep, back into this "donut" then the donut will force outward and make a bulge in the outside of the neck. That can cause chambering problems, or worse.
After LOTS of firing, the brass near the head of the casing is probably getting thin (that's where the excess brass forming the donut is coming from). So it's worthwhile to hacksaw a casing down the middle every once in a while to see how your "pile" is progressing.
The act of sizing brass makes it more brittle and moves brass around as well. (bend a coathanger enough and it eventually breaks -- same principle. The forming is probably more harmful than the heat of firing...) I think annealling the case mouths reduces these tendencies - but it seems like a lot of work so I can't be bothered.
Ideal situation (IMO) would be to use once fired brass from your own chamber -- size necks only with collett die. Use shoulder bump die to knock them back a bit if they start to get tough to chamber after 5 firings or so. Neck turn at the start ONLY if neck thickness variation is garbage (a lot of work) And then uniform from teh inside with a mandrel and neck turn right down to the shoulder after 4 firings or so ONLY ENOUGH to clear that "donut" out of the way. Or run a reamer through before resizing every once in a while to do the same thing.
Do you have a ball micrometer? - what's your neck wall thickness - more importantly, how consistent is the thickness. Possible that you have minimal runout becasue a straight die is keeping things straight -- btu there could be some heinous neck tension things going on. Also - seriously check (by cutting and visual inspection) the case wall down near the head of a few samples. Accuracy aside, I'm curious if you're on the road to a head separation...
This describes my reloading process exactly except that I am not checking for donuts and do not neck turn with mandrel again after the initial turning. I will run with this thought. Thanks.
Yes I have a ball mic. The necks are consistent as they were turned. I think I'll do what you said and cut a couple of them open and see what's going on. I'm probably going to toss these anyway and start with a new lot and see if I experience similar results after 5, 10 firings, etc.
