Re: Virgin Valley
Just to give you some more information about large diameter cartridges on the Encore frame, Before I got into building firearms, I called up Virgin Valley and asked if they could make me a 7.21 Tomahawk Encore handgun barrel if I sent them a 15" stainless steel barrel blank.
I was concerned about the diameter of the round being roughly the same diameter as a 338 Lapua case. They said there was no problem and that they had made alot of these with no problems.
Well, for the barrel back, pretty quick as well and took it out and did some barrel break in and load development. The handgun was amazingly accurate, in fact it is still the most accurate Encore barrel I have ever shot, rifle or handgun. It would consistantly keep three rounds under 3/8" all the time, not average, but all the time. I would say the average group size was a hair over 1/4" at 100 yards, flat out amazingly accurate.
Only problem is that I shot 20 rounds of brass and loaded them back up and noticed I had trouble chambering the fired cases even after full length sizing. If I lowered the FL die as much as possible, I could just get the frame to close if I slapped it shot smartly.
Well, I was willing to live with this as the handgun was so darn accurate. Went back out to test some higher pressure loads and the first shot I took, the case head seperated just ahead of the case web on one half of the case.
I thought that was pretty strange as the load I had was actually still pretty mild in pressure. Cleaned the bore up and shot the next load up. THis case did not have full case head seperation but there was a hair line where the gas was just starting to cut through the brass.
I was a bit baffled now. I went back and pulled the loads figuring they were just to high in pressure. Velocity was pretty mild with the 140 gr Ballistic Silvertip I was using but again, if it would be this accurate I could live with it even though I was getting just barely more then 7mm-08 velocities.
Took the new lower pressure loads out and again the first shot did not seperate but had a very shinny line just ahead of the case web indicating the pending case head seperation.
The next shot cut clear though the case. Looking at all the cases that I had shot for the second time, they all were splitting only on one half of the case, not total seperation all around the case, only 180 to 90 degrees around the case.
I fired one more round and paid attention to where the seperates occured in relation to how the round was positioned on the chamber. That round seperated at the very top of the case in the chamber. Tried one more and same thing. Back to the loading bench I went.
I figured I had some very bad brass with very thin walls.
I measured the case wall thickness on a box of virgin Lazzeroni brass and while its consistancy was terrible to be honest, it was not thin enough to cause these problems. I then measured some of the once fired cases and found that every one had one side of the case wall that had thinned to around 10 to 15 thou.
I loaded up some more virgin cases, this time marking them so I could index them in the chamber and keep track of where the seperation occured.
On those cases on the first firing, there were no case head seperations at all and these were loaded to very high pressure, full 7.21 Tomahawk load levels. Accuracy was amazing again as usual. Went back to the bench and checked the case wall thicknesses and found they had thinned from around 35 thou as virgins to again around 10 thou after firing and in every case, the seperation occured on the top dead center of the case when chambered.
About this time I read a warning about using large diameter cases in the Encore because the increased bolt thrust would result in frame stretching and even damage because of the relatively weak locking mechanism of this handgun.
I got to looking and that was exactly what was happening with my 7.21 Tomahawk. When fired, the thrust from the case would force the frame back and while it went back, it also rotated down which allowed the top of the case to stretch rearward more then the bottom of the case and that is why the top of the case always seperated. The bottom would thin significantly but not enough to case a seperation.
I sent the receiver back to Virgin Valley with the barrel and asked if they could check it out to see if the frame was damaged. It was returns saying they could not tell if there was any receiver damage but that they had stopped offering the Lazzeroni chamberings in the Encore because of issues just like this!!
I then sent the receiver to T/C and they said the frame was indeed stretched but that there was no warrantee on the frame because I used an aftermarket barrel chambered for a round that was to large in diameter.
Now that Encore frame is limited to using only big bore handgun chambered barrels such as my 50 AE and 454 barrels which work fine even with the stretched frame.
In my opinion, while the belted magnums are offered in the Encore, I still personally feel with what I have learned since that time that I would not recommend anything larger then an '06 case head size in a round designed for pressures higher then 50,000 psi.
If you want a real powerhouse, get a bolt action handgun and build it right for that intended purpose.
Now I have a +$400 barrel that is a legit sub 3/8" shooter that works fine as long as you only shoot virgin cases that cost more then $2 per case and then your risking severe frame damage if you continue their use.
Live and learn I suppose, I would recommend you do not do the same thing I did.
I did see they were offering these chambering still that you mentioned and just had to shake my head in amazement.
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