Finaly found that elusive pressure sign.

[4xforfun]

BAT "M" 8.5....300 wby
Spencer 30" ten twist...This is my LR hunting tube...not a match tube....I tryed, but it didn't work out after 700+ development rounds.
210 VLD or 230 Hybrid.
LOTS and LOTS and LOTS of Retumbo


With four firings on the brass I was yet to see any PSI signs other than slightly loose primer pockets after three firings...and the EXTREAMLY high velocitys....3260 with the 210 VLD's and 3200 with the 230's ( )!! I have 6 BBLs for this gun, and the other 5 show normal pressure signs (with "normal" loads)when I push them......and I push them all just so I know, for future refferance, when I am getting close....so I know where the "end" is. This tube also showed "normal" signs of psi...with one more grain than my currant load I saw slight cratoring of the primer, and with yet another grain I got a slight hitch at the top of the stroke when I open the bolt. So, I went back the two grains, where, by the way, it shot great.

To me, anyway, these are "normal". I have no hard bolt lift. I have no ejector marks. I have slightly loose primer pockets after 5 firings.....all is right with the world!!

I do need to FL size my brass which I suppose is a sign. I also use the Larry Willits (sp) collet die after each firing also...kind of an experiment.

Now, finaly....Finaly...I found THE sign that would worry anyone. I went to prime the brass and I could hardly get the shells into the RCBS shell holder. In fact two would not fit at all. The case head has expanded in the web area between the rim and the belt. Everything chambers just fine. I always take my bolt apart to test the fit. Not a lick of evedance of out of speck brass. I suppose if I had measured the web I would have seen them growing after each firing...but I NEVER check that ...ever.

Not sure why I am writing about it, other than I have never seen this before. Sure, I have seen expanded webs...on my dasher, that would not fit the shell holder, but that was after a severly blown primer ( an entirely whole nother story..."the Exploding Gun Saga" that was discussed for years at matches and over at BR central). Has anyone ever seen this PSI sign show up FIRST? I KNEW that PSI was extream by simply looking at the Chrono numbers...numbers which were confermed on several days on different chronos. In fact, I actully had to bump the numbers a bit to get the drops on the three computer programs I use to match the real world drops I was seeing on target.....out to 1400 yards. But, I had no other (obvious) PSI signs.

I guess I find this interesting...but I am wierd. :-[

 

[madderg]

If I'm not mistaken max cup pressure is around 55,000...it sound like you were an the high side of 55K on your way to 60K. What was your trim to length flow after firing? Did you have to trim a little or a lot?

 

[alf]

Tod,

I've found shell holders vary in dimensions too.

I've had brass that wouldn't fit in one, and slid right in another.

Might try that iffen you have an extra.

 

[FroggyOne2]

What Alf said.. that was my first thought.

 

[4xforfun]

Alf,

True, there is certainly some variation in shell holder size. They fit in the shell holder on my Press. I have had another RCBS shellholder on my Priming tool forever. The brass fit fine the first four firings in my priming tool, and I am pretty sure that the shellholder didn't shrink in the last week. I know that this is a WAY hot load....3200 FPS out of a 300 WBY with a 230 Berger is more than most are getting with the 30-378!!! I have primed brass, or tried, anyway, that simply would not hold a primer anymore. Lots of high PSI loadings. NEVER have I seen this. And add the fact that when I tried to load my old dasher's brass after a blown primer, the case would not fit in the shell holder. Thus, I assumed (I know, I know) that it was related to extream overpressure.

I am going to find some more brass from the same lot. I think I have some unfired and I also have some that were treated ...er...with a little more respect.

Do you not think that this is a pressure sign? Like I said...I have been at this game for 25 years...before I got into the LR-BR game, EVEYTHING was maxed out!! You know...Velocity is king (as long as it was accurate, of course), and have loaded/reloaded tons of abused brass. This is just new to me.

And for those who have the internal balistics program, my load with the 230's is 87 gr Retumbo. 88 gr with the 210 VLD. Anyone able to extrapolate some pressures from that data.

Thanks,
Tod

 

[BoydAllen]

A long time ago, a friend asked for my help on a project. He wanted a reamer designed for a tight necked, shorter throated .300 WBY, and I managed to do that for him. I also helped with load development. We loaded, at the range, and chronographed every shot. Since we had no load data for that chamber design, we started low, and stair stepped up with half grain intervals, using the same case. I won't bore you with all the details, but one of the things that I did was to mark the head of the case with a line across the diameter (permanent marker) and measure the diameter of the belt of the unfired case, and after every firing. On the first firing, the belt diameter increased slightly, after that, for several more firings, including some that showed an ejector mark on the head, it did not, until finally, it moved again, and we stopped the increases, noted the ambient temperature, backed the load off a full grain, and called that our maximum usable load. The rifle shot fine, and it performed well in the field.

IMO, you might consider starting with a new case and doing a test that is similar to the one that I described. From what you tell me, I think that you are playing with fire. Chronographs have this effect on many people. The metal does not care what you want, and if it fails, you could get hurt.

 

[Minesweeper3433]

;D Just saying this with a helping of sarcasm but you sound like you need supervision at the reloading bench.

 

[4xforfun]

Donovin,

I agree 100 %...every tube is different....every EVERYTHING is different. And yes, my throat is LOOOONG...My OAL is over 4 inches.

Boyd,

I agree with you 100 % also....BUT....I had done all of the load development WITHOUT a chronograph. I relied totally on the gun to tell me where to stop. My initial load development for the hunting loads was with Retumbo and the Berger 210 VLD. 88 grains shot great...no PSI signs. 89 gave me a slight catering of the primer. 90 gave me the same cratering, along with the little "hitch" or "click" at the top of the bolt throw when I ejected the brass. Thus, I backed off the two grains...back to 88....where it shot GREAT. It wasn't until I started working on my LR drops that the chrono came out of the closet. So the idea that "the chrono made me do it" is untrue. If anything, the chrono made me VERY AWARE. It had me checking my brass very carefully after each shot...desperately looking for the PSI signs...which never showed up...until now...after the 5th firing.

Also, when testing this tube for 1000 BR comp with RL 25....I did use a chrono...for ALL testing. I got the same sequence of "warning signs" as the hunting loads with Retumbo...but at more "normal" velocities. First the cratering..then the hitch, then came the shiny extractor marks. I never took the retumbo to that point...I knew it didn't matter how good it shot. It is to expensive and to dangerous to go there. The chrono is why I have been keeping a close eye on the whole thing....the velocities were way high.

 

[Hunkyfish]

Thx for the post & replies guys
I just won a NRA Weatherby Mark V 300 Mag last week at a Friends of the NRA dinner last week & I will have to reload to be able to shoot it,
All info for this caliber & gun is appreciated

 

[4xforfun]

;D Just saying this with a helping of sarcasm but you sound like you need supervision at the reloading bench.

Ok..so as non sarcasticly as i can be.....what would you do different? You must have someting in your head to have made that statement.

 

[TonyR]

I think I may have had a similar experience. I hadn't really given my symptoms much thought until I read this post because the gun shoots fine without load problems; but I wonder if variations in the extractor groove diameter has anything to do with what you experienced? I used extractor groove expansion on the first firing as a pressure indicator when I was doing my initial ladder test on a new magnum cartridge. The action is also a BAT M. I measured all of the extractor groove diameters before I fired any of them. I don't recall the extreme range but it was several thousandths of an inch. My normal match loads are probably about a grain off the QuickLoad max and I also get occasional tight fits in the shellholder with this brass even though I get none of the obvious pressure signs during F class matches with this gun in a wide range of temperatures. And the tight cases do fit some shellholders better than others. I also saw different exractor groove expansion with different brands of brass. In one test sequence, brand R required an additional 1.5 grains of powder over brand N to get the same groove expansion even though the cases weighed the same and gave the same muzzle velocities with the same powder charge. Just my $0.02.

 

[Minesweeper3433]

;D Just saying this with a helping of sarcasm but you sound like you need supervision at the reloading bench.

Ok..so as non sarcasticly as i can be.....what would you do different? You must have someting in your head to have made that statement.

I just don't push my loads anywere near that hot. If I want more velocity I get a longer barrel.

 

[TC260]

I just don't push my loads anywere near that hot. If I want more velocity I get a longer barrel.

...or go to a bigger case. Why push a 300 wtby to insane pressures to get 30-378 velocities when a 30-378 can do it without the risk.

 

[Webster]

Something I have always thought about. Can someone comment that has a pressure sensor on their barrel. Most of us know the signs of excessive pressure. If we see signs of pressure and back off a little and don't see the signs of pressure are we still above the pressure that the action is rated at by the factory. Are we operating at some safety margin above the action rating?

 

[Forum Boss]

Now, finaly....Finaly...I found THE sign that would worry anyone. I went to prime the brass and I could hardly get the shells into the RCBS shell holder. In fact two would not fit at all. The case head has expanded in the web area between the rim and the belt. Everything chambers just fine. I always take my bolt apart to test the fit. Not a lick of evedance of out of speck brass. I suppose if I had measured the web I would have seen them growing after each firing...but I NEVER check that ...ever.

First, yes I have seen this phenomenon in a .260 with a generous factory chamber. As you probably know, expanded case heads like this are a sign that you are WAY overpressure.

I have recommended to people that they bring a shell-holder to the range during load development. As you're working up to "redline", check your brass. If it's hard to put in the shell-holder you need to stop.

Having said that, I want to make this clear: This is only ONE sign of pressure. You can have an over-pressure situation even if the brass fits fine in the shell-holder. I do NOT advocate loading up until the shell won't go in the shell-holder. What I am saying, is that the use of the shell-holder test as YET ONE MORE INDICATOR, can help you know when to definitely stop and move downwards to safe levels.

 

[remdriver]

Can someone tell me when measuring the extractor grove with a blade micrometer on a 7mm rem mag how much growth is to much ? Or should I measure just ahead of the belt and how much is to much ?
Thanks Will

 

[BoydAllen]

You are working too hard. Mark the head so that you will take the measurement in the same place, and measure the belt. Start with an unfired case; run a pressure test with increasing charges, all on the same case. You will end up with your own data for that brand of brass. Start in the middle of the book, and for a magnum, half grain steps are plenty small. The only issue would come up if the diameter of the belt section of the chamber was very tight.

 

[4xforfun]

;D Just saying this with a helping of sarcasm but you sound like you need supervision at the reloading bench.

OK..so as non sarcastically as i can be.....what would you do different? You must have someting in your head to have made that statement.

I just don't push my loads anywere near that hot. If I want more velocity I get a longer barrel.

First off, I had no clue that they were hot. I started low, worked my way up till I found the PSI signs...Slight primer cratering( at 89 gr), and a slight hitch at the top of the bolt throw when ejecting a fired case (90 gr). I backed down to 88...no sign of psi. And quite simply, that was where they grouped best on out to 750. Now, if I was like 95% of the reloaders on the planet, I would be done....simply because that 95% don't own a chrony. If I hadn't been working up drops, I too would have been done. If I told this story, but instead of telling you up front that it was a hot load....if I simply asked about the psi signs I was showing, even you would have said...yep, you are good to go.

And, as a side note...just finished the SIXTH firing of the cases today. SIX. How many people out there are getting six firings (or more..these cases still look good...I checked them for the possability of case head separation in front of the belt...good to go) out of a belted magnums?

And to say what you said simply because it is not how you go about things is ridiculous. A hint about using sarcasm...you better be the smartest person in the room if you are going to be sarcastic....no one wants to hear the village idiot spew sarcasm. It just don't work!!

Just sayin!!

 

[4xforfun]

Now, finaly....Finaly...I found THE sign that would worry anyone. I went to prime the brass and I could hardly get the shells into the RCBS shell holder. In fact two would not fit at all. The case head has expanded in the web area between the rim and the belt. Everything chambers just fine. I always take my bolt apart to test the fit. Not a lick of evedance of out of speck brass. I suppose if I had measured the web I would have seen them growing after each firing...but I NEVER check that ...ever.

First, yes I have seen this phenomenon in a .260 with a generous factory chamber. As you probably know, expanded case heads like this are a sign that you are WAY overpressure.

I have recommended to people that they bring a shell-holder to the range during load development. As you're working up to "redline", check your brass. If it's hard to put in the shell-holder you need to stop.

Having said that, I want to make this clear: This is only ONE sign of pressure. You can have an over-pressure situation even if the brass fits fine in the shell-holder. I do NOT advocate loading up until the shell won't go in the shell-holder. What I am saying, is that the use of the shell-holder test as YET ONE MORE INDICATOR, can help you know when to definitely stop and move downwards to safe levels.

I agree..there are lots of PSI signs. like I said..first came the slight cratering of the primer, the next step up gave me the issues when opening the bolt. That is were I stopped and backed down 2 grains. Like I said..I take ALL of my guns/tubes to the very edge...it lets me know where it is and also tells me how the gun acts on the way there. Based on how this BBL had acted when I was working up loads for 1000 yard comp, I am sure I could have gone two or three more grains. Never got to the shiny ejector marks or VERY stiff bolt opening. I didn't see the need..been there, done that with this tube...I knew how it was going to react. BUT...I had to fire the brass FIVE times before the next symptoms showed up. Most belted brass is chucked before they ever see the fifth firing.

Thanks,
Tod

 

[.260 james]

Just out of curiousity did you change Lots of retumbo or see different weather conditions. I have seen and heard of first account testimonies of Retumbo doing strange things at strange times in 7mm mags and especially .30-378s. All involved changed to H1000 and have never been surprised again. Maybe not the same speed but no more gas bath surprises either, with formerly good to go loads.