Exploding gun part two

T

Tod Soeby

New member
I'MMMMMMM BAAAAAAACK!!:eek:

Gun is acting up again......6mm Dasher, .271 neck Rem 700 action, bolt is bushed....standard stuff. I have loads left over from last fall which don't give me any trouble. The stuff I loaded yeasterday.....stuck bolt....blown primers....poor accuracy.....standard stuff :D.

Comparison of the two loads

Good....velocity- 3050
bad.....velocity- 2990

Headspace...fired brass (the numbers include the length ot the tool) 3.2580
good loads....3.2565
bad loads....3.2575

Neck diameter...good .2690
bad .2685

Powder charge....same
Primers.....same carton
brass....same lot, weight sorted.
bullets, same lot #

Powder I think it came out of the same jug, but can't remember.

Chamber was clean and dry...no oil or residue......same with the brass....they are wiped down with break clean before I put them in the shell box.....which is also clean and dry.

I shot both of the loads yesterday, so the temp, humidity, ect...were the same.

I am at my wits end with this thing...I am sure you guys remember the thread from last year on the first go around. I have gotten a lot of new measuring tools and new custom dies since, but am now back to square one!!:mad:

The bad loads have less velocity (60 fps), more neck clearance (.0005), less head space(.001), weigh the same, ect.....but just plain friggen dangerous!!:eek:

I planed to take the gun to Iowa next week, since I am no where near ready with my other gun.

Looks like I got some work to do.:confused:

Anyone have any ideas??

I am all ears (and belly).

Thanks,
Tod
 
ok silly stuf.
measure the old loads to confirm oal/ogive length.
check against the new ones.( just do it)
now take 3 or 4 of the good ones and tear them down...carefully.
weigh the powder.....is it realy what you think it is for weight ?

check the primer hole dia.....just cause....maybe the bads are small, popping the primers but not getting a good powder burn ?( i said silly stuff)

how do you measure powder...they can very lot to lot.

no i dont know why...but how do you explain popped primers , less case expansion and less velocity.


mike in co
 
More silly stuff.....

Donuts? Carbon ring in the bore?

Bill
 
A couple thoughts.
Are you sure you didn't get ahold of some pistol primers instead of rifle?

Is the case properly trimmed to length?

As Butch said you may try another lot in case somehow the wrong powder got dumped into the canister you are using, that doesn't make much sence to me though with the lower velocity.

James
 
Tod Soeby

Tod
The only time I see problems like that is with RE15.

Which lot# of Varget are you shooting?
Lynn
 
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All of the remaining loads, both old(good) and new (bad) have been measured for OAL and with a bullet comparitor. Even if the bad loads were longer, the neck tension is so low that when I close the bolt, the long bullets get pushed in. This not how I load them, of course, but I have done some "what if's" to see what would happen. I puled the bullets and weighed the powder , cases, and bullets.....all the same. The load is 32.6 RL 15 (sorry Lynn :eek:). I know I used RL 15 because I had just finished off the can and chucked it. As far as a cabon ring.....I am a clean freak, and both the loads were shot at the same time. I can't see only one load being affected by a carbon ring. All of the casses measure the same trim lengh. The only differance in the brass is that I neck turned them at different times, thus the .0005 difference in neck thickness. I do not own or load for a pistol. I have never even had a pistol primer in my loading room....CCI 450's is what I use. As far as donuts....I measured all of the cases with the blade of my caliper all the way up to the neck-sholder juncture.....no variation at all in thickness.

The brass all came from the same box. I could see having one bad piece, but I fired 10 of both loads, All 10 of the good stuff was good...all 10 of the bad stuff was BAD.

I N E V E R dump powder from one can to another....if I have a little left in a can....its 4th-of-July-city, baby!!!:D

I use an older RCBS 505 ballance beam. I check the scale by pulling out a box ot 210 bergers and weighing a couple of them. Never off by more than 1/10th gr.

Keep up with the questions (except the guy last year who asked me if I owned a loading manual:mad:). Who knows....we may stumble upon an answer yet.

Lynn, I am going to pick up some Varget next week.....any special loads you can share with me????;)

Thanks,
Tod
 
Tod,
I would try more neck tension. I had a problem a couple months ago with leaky primers using RE22 with light neck tension and a squeeky clean lubed bore on another 6mm ctg. I am playing with. After the barrel was fouled the problem went away. I believe the problem to be related to too slow of a build up of pressure, then a spike.

James
 
Tod Soeby

Tod
If your shooting a straight 6BR the standard load is 30-30.5 grains of Varget a CCI 450 Magnum Primer and hard into the lands.It will give you roughly 2850 fps with the barrels we use.
The hotter load is around 2970 fps and is 0.2 grains below where the primers pop.It will work with all 100-107 grain bullets.

RE15 is a great powder if you want to develop a new load for each 5 degrees of temperature change but why bother.Pull the bullets on a couple of the bad loads and pour the powder into your palm.If its clumpy and gooey its the powder breaking down.Take a Q-tip and run it around the shoulder area of a non-fired case.Does it look reddish? Out here we shoot when its real hot like in the 110 degree range.If your ammo is sitting in the bed of your truck and your using RE15 all I can say is good luck.
At the upcoming nationals I hope everybody there is using RE15 except myself.
H4895 is another powder to look at.
Lynn aka Waterboy
 
Butch said it but try pulling the bullets and using the old powder charge in the "good ones" in the "bad ones" case. I am betting its the powder. Silly but I read your post over and over and it seems to be the only thing that stands out. I have seen huge differences between lots.
 
Tod, have you determined the chamber neck diameter is really .271? What's the diameter of a fired neck? -Al
 
Have you checked your true trim length . Not print dimensions, but
the actual chamber. Since this is a derivative of the 6 BR and
there are 2 different lengths plus what your chamber may be, I
would look at that. A brass plug instead of the steel ones is
much preferable
 
The trim length on the fired cases.....good 1.552
Trim lenght on the Bad cases.....1.525.....they are shorter?

I will actualy pull more bullets and get the unfired case lenth lator today. Maybe swap the powder around and try them.

Neck dia on fired cases .2715. So there is plenty of clearance.

As far as a squeeky clean bore....my 23rd shot stuck the bolt, blew the primer, ruptured the case, and the brass flowed way into the ejector hole.....WAY IN....I had to use my leatherman tool to pry it from the bolt face.
That is when I retired for the day.:mad::eek:



You guys are talking bad powder......evedently the velocity is not an issue, as the bad loads are a full 60 fps slower than the good. You can have higher psi with slower velocitys??

I am going out now to do some load work on my other gun.......As the Calif. Governator says....

I'LL BE BAK!!!

Thanks,
Tod
 
You can have higher psi with slower velocitys??

Tod,
I don't know about rl15 but i had a similar experience with varget when i changed lot #'s. higher pressure slower velocity and even a lighter charge when i maxed out. since you are not sure if all loads came from the same jug of powder i would suggest get a new/different lot of powder and try it.
Gary
 
Tod Soeby

Tod
The smallest lightgun group ever fired at 600 yards was done with a 6Dasher and Varget.
When you switch let us know what happens.
Lynn
 
Tod,

Just a guess, but I'm thinking when you rupture a case, not all the pressure is pushing the bullet, hence lower velocity. Not necessarily lower overall pressure, but still red zone.

Al
 
alf said:
Tod,

Just a guess, but I'm thinking when you rupture a case, not all the pressure is pushing the bullet, hence lower velocity. Not necessarily lower overall pressure, but still red zone.

Al
Click to expand...
That could be true, but I ran the last 10 through the chrono (including the last shot that went WAY wrong) Low velocity -2991 High velocity -2998...ES of 7fps... Of those, I had 3 stuck bolts and 5 blown primers and all left at the least shiny extractor marks.


I have a brand new, unopend 5 LB jug of RL 15 and 200 new, ready to fire form brass (primed, necked up to 25cal and necked back down part way to 6mm). What I should do is chuck ALL of the old brass and start anew.


OR SELL THE POWDER, 1300 SORTED BULLETS, BRASS, DIES, ECT.... AND REBUILD TO SOMETHING ELSE!!:eek:
 
Chisolm said:
Tod,
I would try more neck tension. I had a problem a couple months ago with leaky primers using RE22 with light neck tension and a squeeky clean lubed bore on another 6mm ctg. I am playing with. After the barrel was fouled the problem went away. I believe the problem to be related to too slow of a build up of pressure, then a spike.

James
Click to expand...

I was using way more neck tension during round one of this last year, as I didn't have a bushing die yet.....One of the the things I changed when I got my new custom die was use less tension....I thought it helped because the trouble went away........FOR A WHILE!!!!

Keep 'em comming!!:)
 
Tod, from what I can tell you are doing/using something different with your ammo. The rifle remains the same yet the ammo acts predictably different. If I had a bolt become stiff unexpectantly, I would stop shooting.

I use 105's and 108's, Varget and run at 2970 in my 6mm Dasher. I need to drop .2gr of powder for 105 lapuas but still get 2970. If I don't drop the charge the bolt lift gets stiff. Bushed my bolt head and Forster full length sizing die. Lower velocity than I would like but unless Re17 works and becomes available here there's not much I can do.
 
Varget is my preferred powder with .308 Win. One time I came across a bad lot of Varget that caused maximum pressure without developing the correct velocity. I was shooting my standard load (that I've used for years) in the same rifle. The problem went away after switching to another lot of Varget. One of my shooting buddies had the exact same thing happen with Varget.

- Innovative
 
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