I have a bunch of this stuff and ran it in Proof pre-fits pretty well. Brass now has 8+ firings on it and doesn't work any more. I'm trying to get to the bottom of this issue.
I have annealed it on an AMP after every firing.
At a match in February though, I had such a hard time closing the bolt on most of the rounds, and extracting them, I withdrew from the match. I was fighting the gun every round. That was with an old Proof prefit I had ran in 2020.
Got me a new PVA barrel and they use Lapua reamers. I bumped the hell out of this brass thinking they were too long. Seated the bullets with an extra long jump. Still had issues at the last match. Though not nearly as bad as with the Proof barrel.
6-Dasher
Original Alpha brass 8+ firings
Proof prefit from my 2020 season
SAC full-length sizing die.
What happened to the old Alpha stuff that caused them to switch to OCD, and is this what I'm experiencing now? I just want the skinny, so I can figure out if I need to go back to Lapua brass or Redding does again. Thanks!
We mark the chamber as "Lapua" as opposed to anything else because of the trim length. There are 2 Dasher trim lengths on the market: There's the Lapua based print and there's the Norma print which is sometimes called "Long Neck" brass. The Norma brass from 2015-era had a longer neck on it and required a different reamer which I also have. That "Norma" brass has its own issues and stories but it's pretty much forgotten around here now because the company that was importing it has closed doors and nobody's got any of it left. Those reamers sit in my storage drawer in case someone orders a barrel but it's rarer and rarer every year as the brass gets cycled out.
Our reamers and the Alpha reamer print match within 0.0005" on every body dimension. I've spent time on the phone with them about it too. Alpha's doing a great marketing job of telling people to use their reamer for their brass, I had trouble with their reamers cutting the way we need them to in my equipment. They cut great at manual equipment speeds. I had trouble doing anything meaningful in the turning centers that I have on the floor here.
I've had them and I measure them on our optical comparator, it's the same thing as we're cutting and labeling as "Lapua" which is due to the trim length only.
I've cut the same print for 8 years in Dashers, it's just that now the market finally caught up to what we've been doing since 2014. The necks are opened up to 0.274-0.275 and the freebores have been opened up as well. A lot of the early issues in Dashers for PRS guns came from people using "no turn" reamers that were 0.271 or 0.272 necks and they simply weren't up to the task of a 300+ round weekend.
On the brass side and "PVA has too much unsupported web"... this was marginally true 2 years ago but misses a litany of other factors involved. Not the least of which is how the brass was treated/loaded, how the brass was made, etc. We made Dashers for 5+ years before Alpha brass showed up, then a few issues happened.
Since 2020 I have had 3 problems out of over 5,000 barrels delivered. Without getting too far down the rabbit-hole it's multiple issues rolled into one case that is pointed at the gunsmith. One client swears it's not an overload on his part but the brass remains show a flash hole that was so big a primer almost fit through it. That's also on an action where the receiver maker pointed his finger at the gunsmith (me) but when the gunsmith (me) offered to buy the new action on condition that I was given the action in question he flat out refused. There was absolutely no way he was going to let anyone see that receiver. He knew full well I was immediately going to send it to a metallurgy lab for testing because some of the damage didn't look right for an action that was properly heat treated. When the chamber chamfer was called into question we reviewed the print published by the company and their callout for what they intended and what the international GD&T standards define were backwards. The event happened 1100rd into the barrel life with a load that was VERY warm. The guy swears the load wasn't very warm but again the flash hole was massively enlarged.
We changed our chamber chamfers on every single prefit we make as a result of the new brass coming into the market.. There was an Origin that went recently. Origins have never had more than 0.165" of unsupported case web but this one was blamed on "insufficient case support" by people including
@Bravo6niner.
The brass that let go was multi-reloaded in a chamber with 0.165" of unsupported web. Any Remington chamber with a 0.005" break on the chamber mouth has 0.165" of unsupported web. Apples to apples.
So why did it let go? Brass problem. The origin thread a few days ago had nothing to do with a chamber chamfer issue and everything to do with a brass problem.
Here's a screenshot of the data from Lapua 6BR brass that I measured 100pc and performed a mild statistical breakdown of the data.
Mean-2s is 95% or 5/100 will fall outside that band, here we find 5 pieces in the sample set just like predicted.
The Mean-3s line is 99.7% or ~1/300 --> there is 1 piece measured there which is within prediction as well.
The Mean-6s line means Average minus 6 SD's, which is approximately 1 in 1,000,000 pieces will fall at that level. This number is 0.1754" thick web
This same measurements on old Alpha brass brings the 3 sigma line below 0.170 and the 1 ppm line to 0.165
Read that again. That means that a "proper" chamber chamfer on a Remington is line to line with the brass. That's also line to line on several other actions on the market that are 3 lug designs with their currently published tenon prints.
This doesn't go into any discussion about corner radii in the brass or hardness of the material. That's a whole additional discussion and I'm compiling an engineering report on it now.
So what, that's 1 piece of brass in a million pieces.
We have chambered and delivered over 10,000 rifle barrels since 2014. One piece of brass in 1,000,000 means that somewhere in the 10,000 barrels we delivered it only takes 100 pieces of brass going through each barrel before someone will find one that's bad (100 x 10,000 = 1,000,000).
Most folks have 300-500 pieces rotating, some more.
There have been 3 events with our barrels. All from the same brass maker, all from the same generation of brass, and 2 of the events have happened where there's more support than "line to line". There was an event with another gunsmith and the gun was inspected multiple times. No problem. The brass was sectioned and found to be cutting itself apart at the wall to web radius junction. It cut through to the extractor groove and let go.
We made a change to react to the market's demand to use a different brass and we updated our practices when we found out that there's a potential weak link when our product is combined with someone else's product. I have spent hours discussing this topic with several gunsmiths who have seen issues, we've made changes and so have many others doing what we do. When the problems continue there's something else to look at beyond the chamber mouth chamfer.
There's a decision chain that involves each party with liability in this single case. I agreed with the action maker to replace the action if I got back the one that was damaged. He refused flat to let anyone else see that action. Why? The flash hole picture speaks to an overpressure event that should not have damaged a receiver. Even at 85ksi a Dasher doesn't generate as much bolt thrust as a 6.5 PRC does under normal conditions. The action lugs should not have taken a set back. At the time I had no idea there was a problem with the brass that was looming on the horizon. Yet we're blaming the gunsmith as the sole perpetrator when it's likely that the brass had a problem, the reloading practices had a problem, the action had a problem both by design and manufacture, and a gunsmithing practice that was tried and true for years suddenly was no good anymore.
It's my opinion that using the words below to describe our chambers is erroneous or at best partially misleading. "Typically" would describe something that was more than 3 in ~10,000 or ~0.03%. According to our geometry in place for years, even before changing it the factory feed cone in an Accuracy International barrel would be wildly unsupported as they've always had more case head sticking out than we have ever made. How often do they let go? Extremely rare. When they do have events are the receivers destroyed? Even more rare.
So is it a gunsmithing problem or is there more at play here?
I think it’s a two fold problem for you. Gen 1 brass was a bit soft and thin in the base area and PVA barrels typically have to much chamfer and that leads to unsupported case head issues
We do listen to the market, we do make changes to react to product updates, and we do our best to make sure that we aren't doing something dangerous. I've been audited by my liability insurance company to review our practices and our manufacturing record keeping logs. The fact that we have those logs to begin with is an anomaly in the custom gun world. It blew the auditor's mind when I had an access database with the information in it.
I can only do what we have control over to react to new products in the market. When something has worked for years with nationally distributed products and then all of the sudden there's a safety event we take it seriously. This means digging into the root cause. If that root cause doesn't lie with us I still see if there's something we can do to make a change to mitigate safety risks.
It sounds like the new OCD brass is a modification/improvement to fix an issue that has to date been blamed on people who fit barrels. I'm glad they're making product improvements.
