Thanks for the in depth response. As mentioned in original post, I'm pretty experienced on loading, shooting, and rifle parts/repairs however, novice in machining at best. I do have a bore scope and have examined the chamber, throat etc best I can. I do not see any obvious grooves. I have also checked cleaned cases with micrometer and have found no bulges in the fired cases, or any other obvious damage to brass. All is to length. I resized some cases bumping shoulder 2thousandths and refired with "safe" by quick load and known to me loads with the same sooting as new brass and annealed new brass. I also neck only sized some without moving the shoulder at all. Same thing continued to happen. This makes me think you are correct in that there is just something minor inside that isn't allowing shoulder to seal case neck. But I have decided to not fire it anymore until I can get smith to look it back over. Still just puzzled. Thank you for your in depth response!
Black soot on cases head scratcher for me???
- Thread starter hweissert
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Set barrel back, rechamber like other rifles.
What I kinda had on my mind too
Hugnot
Well-Known Member
My guess is that the spec length brass is being jammed into front of a non-spec chamber preventing normal neck expansion. My sooty cases were all .030 excessive length.
Maybe. Would make sense to me though for it to be the other way since it is 30 thousandths longer than the other 2 rifles?? As in maybe chambered too deep? I know there's a lot that go into depth etc including tolerance of given barrel. However, just seems odd to me that with same barrel manufacturer, same contours, that this one is that much longer than other 2. The only thing different is the action 2 are LA remingtons. Mine is a LA Stiller Predator
I had the same issue with a 257 bee. I found the problem to be that the bullet was jumping out of the case before the brass expanded I actually was crushing cases from the outside during firing. Scary stuff for me! The cure ended up being a good crimp to keep the bullet from jumping out before adequate powder ignition/pressure. Then no soot and no crushed cases.
Saskquatch6
Well-Known Member
Just curious Traveling Tech - did your 257 Bee have a lot of freebore?- ie: was bullet tail essentially out of case before ogive engaged lands?
Yes. I think most weatherby chambers have like 3/8" of free bore. The bullet jumped out, lodged in the rifling, then the powder fully ignited, pressurized the chamber before the brass expanded and sealed. The brass crushed from the outside and then the bullet was forced down the bore. I bet I had some messed up pressure going on. I hope my experience helps. Rifle was a weatherby vanguard.
Bob Wright
Well-Known Member
Annealing fixed my blowby to the shoulder. Never down the body of the brass though. I size for .003 neck tension, all necks turned with .004 clearance on the dia. of neck. Sounds like an early bullet release affecting the neck sealing. Just a guess though. Let us know what the Smith says.
I've shot new brass, fire formed brass with shoulder bumped 2 thousandths, fire formed brass just neck sized, annealed mag primers, etc. only thing that cleans it up is more powder. Its super accurate with know loads just soots. Crank the powder up, cleans it up, doesn't shoot as well. I don't think Bullet is leaving too early as the factory new has about 4K neck tension and I'm using a 2k bushing in sizer now. Makes a little sense in a free bore bee or wby but this is a 284 Winchester. Not exactly a hot rod. And, my bullets are just touching lands to start so don't have to move much to get them there. Im taking it back over tomorrow morning to Ck head space etc but I'm more on the lines of either a head space issue or, some damage from reamer in throat or chamber like mentioned before
Rflshootr
Well-Known Member
Measure fired brass from both rifles. The chamber may be bigger on the new rifle. It's possible, if for some reason, the reamer wasn't pushed straight it could have made it cut oversize, especially near the base. If the chamber isn't concentric, the throat lead angle could be longer as well.
Sounds like a headspace problem to me. Let me explain why...
Same reamer, same barrel, but .030" greater CBTO. There are only a few options here.
You say that you size to -.002" but how do you know or measure this? I assume your benchmark is from reamer prints or experience with the two previous chambers. When fireforming cases it takes up to 3 firings of a case to approach "actual" dimensions +/- setback or rebound of the shoulder (datum line). If you continue to anneal it takes longer. A set of go/no-go gauges could lead you to an answer. You may be FF'ing to a greater headspace, essentially mimicking a wildcat chamber.
It's not at all uncommon for FF loads to shoot with excellent accuracy. Being able to add powder in this process is accounted for by the cushion of the brass expansion.
Same reamer, same barrel, but .030" greater CBTO. There are only a few options here.
You say that you size to -.002" but how do you know or measure this? I assume your benchmark is from reamer prints or experience with the two previous chambers. When fireforming cases it takes up to 3 firings of a case to approach "actual" dimensions +/- setback or rebound of the shoulder (datum line). If you continue to anneal it takes longer. A set of go/no-go gauges could lead you to an answer. You may be FF'ing to a greater headspace, essentially mimicking a wildcat chamber.
It's not at all uncommon for FF loads to shoot with excellent accuracy. Being able to add powder in this process is accounted for by the cushion of the brass expansion.
I'm going through the same thing right now with a 6 Creedmoor and a second lot of Berger 109s. The first ones shot great with no sign of leakage. The second lot is soot city. My leaky cases necks measure the same if only slightly bigger than a loaded case. My thought is the bullet is sliding out of the case too easily upon initial pressure and leaking pressure until the bullet hits the rifling slows or stops then builds pressure and seals up the leak. I'm getting good speed, 2977 FPS, and accuracy with no load development.
The second lot, older numerically, has a bit of a pressure ring and I believe it's enough to stretch the neck a bit more and allow the bullet to start moving easier/sooner. I FLS my annealed cases without expander and mandrel the necks to size. I use a turning mandrel, .241", set tension. I believe more neck tension is needed. I want to try a .240" mandrel to see if that will cause the billet to stay put longer and solve the leakage problem. 21st Century offers one but says all orders are at least 4 weeks before shipping thanks to COVID and the political climate. I don't want to wait that long for a test. I tried some DTACs wish have .098" longer BTO and are still in the neck when they hit the rifling and they don't have leakage. The original 109s I shot measure .243" and don't have issues, the new to me lot measures .2345" and cause issues. This is likely not being helped any by the long jump caused by the SAAMI spec .183" free bore
I've been in contact with Berger and they are befuddled as well. They think I'm onto something with the releasing too early theory, but as of now we can't prove it. They did say that they do not design in pressure rings to their bullets. It happens occasionally depending on many factors in the bullet making process.
The second lot, older numerically, has a bit of a pressure ring and I believe it's enough to stretch the neck a bit more and allow the bullet to start moving easier/sooner. I FLS my annealed cases without expander and mandrel the necks to size. I use a turning mandrel, .241", set tension. I believe more neck tension is needed. I want to try a .240" mandrel to see if that will cause the billet to stay put longer and solve the leakage problem. 21st Century offers one but says all orders are at least 4 weeks before shipping thanks to COVID and the political climate. I don't want to wait that long for a test. I tried some DTACs wish have .098" longer BTO and are still in the neck when they hit the rifling and they don't have leakage. The original 109s I shot measure .243" and don't have issues, the new to me lot measures .2345" and cause issues. This is likely not being helped any by the long jump caused by the SAAMI spec .183" free bore
I've been in contact with Berger and they are befuddled as well. They think I'm onto something with the releasing too early theory, but as of now we can't prove it. They did say that they do not design in pressure rings to their bullets. It happens occasionally depending on many factors in the bullet making process.
I'm leaning toward the same as you.
When I referenced resizing, I'm referring to bumping the shoulder back 2 thousandths of an inch from a fired case. Ie measure the fired case from new rifle with E 500 comparator and set the die where it only moves shoulder back 2 thou. I then thought well, maybe it is essentially a "unintentional" wildcat chamber so I resized to neck only in hopes this would "seal" faster. No change. The bullet theories above by going to bigger bullet I have not tried but, don't really want to move to a 180 grain in it as the 168's shoot in both other rifles very very well. Even with this rifle, the 168's I'm able to keep .281 of bearing surface inside the neck to touch the lands. Which puts it near the shoulder junction at the bottom of the bullet. I'm not sure how going up 12 grains in Bullet could or would help. I'm going by in morning to check headspace. Maybe that's it.
