210 bergers blowing up?? help 30-378 wby

[bsb]

This is the deal, me and my Brother has been trying to get dialed in for 1000yrds, we loaded some 210 bergers last week in his 30-378 and found a good load with 105Gr of retumbo (shot probably 20 into paper just fine)
with no pressure signs so he loaded up 60 and went to the
range (field) He changed his scope to his other 8.5x25
leupold so we sighted in at 200 yrds well we got it on a 8"
paper plate did 2 shots about a 11/2" apart the next shot
hit nothing no plate or plywood but my boy said he saw
somthing hit about 20' low we thought huh whats the deal!
so we started shooting at 1000' yrds he missed 1st 2 and the dust boiled up each miss as it is in a dry field
then he hit the plate 3 strait let the gun cooldown and tryed it again, this time nothing no dust or nothing but a wiered
twang sound he shot again and same thing, so we picked a
little bush about 700yrds same thing no dust or nothing
just wierd twang sound! so I shot my 168Bergers (RUM) at bush
and the dust flew big time. well all his new brass he just
loaded had pressure signs on the base A 1/8" round imprint
same load as the weeks before it was about 70 degress here today and I am telling you the bullet is going crazy sometimes! It chronoed at 3115 (210 bergers) the week before
so why is it showing the pressure signs could be temp etc I know,but why are those bullets not making the flight?
And one time when He was shooting at the 1000Yrd plate we saw some dirt (about like a dirt clod Threw) being kicked up about a 100 yrs away and the twang sound. when there was a twang sound there was no dust or nothing at targets! when there was no twang sound the dirt flew like a tornado!
please help? we are calling walt berger in morning.
Yes the loads were a little hot for some reason, new cases
or temp or different powder batch, but is it normal to have bullets go bye bye with a little extra pressure?
Dont get me wrong any signs of pressure is unexceptable for us.

[goodgrouper]

I personally have chronoed the 210 Berger VLD's at velocities higher than what you have reached with no problems so I don't think it was the speed that blew them up which is usually the culprit because of the increase in rpm's and resulting increasing the centrifugal force.

I once had a gun that began doing the same thing as yours with the 80 grain Bergers. Used to shoot them into scary groups at 1k but once the throat got a little worn, the roughness was something the Bergers couldn't handle. They would go out there about 100 yards and then poooff!

Switched to the Sierra 80 grainers and they lasted for about another 150 rounds or so until they started blowing up too.

Check the throat on that WBY. If it is rough, you may have to shoot the Sierra 220 MK's. They work great as well.

Good luck.

[bsb]

grouper! thanks you may be on to something will keep you posted.Thanks for awsome response.I did not think of that!
I think those bergers are really soft jackets

We pushed the Berger 210 behind 100 grains of H1000 out of a 34 in tube at 3300 fps. We did not witness what you are describing but they wouldnt group worth a crap.

When then swapped to Berger 190's and using the same load we pushed them to 3600 fps. Accuracy was good but the barrel needed to be cleaned or the pressure would increase after around 10 shots.

Copper fouling build up caused a smaller bore AND carbon build-up in the space between the start of the case mouth and begining of the throat.

This carbon build up caused some serious pressure signs after about 10 rnds and needed to be cleaned as well as the copper fouling.

Is this a true WBY rifle? If so it more than likely has loads of freebore and can be subjected to the same carbon build-up as well as horrible copper fouling.

Inspect the bore and pay particular attention to the throat area.

I have yet to dust a Berger bullet but d-a has done it in his 257 STW but thats a bit different story of say 3700 fps area.

The 1/8th round imprint is the ejector mark. This carbon build-up can cause the area of the chamber where the neck seats to become smaller and this will increase your pressure to extremes.

Dave

[speedbump]

Roy, back when the 7mmRUM was a not-yet-released thing, I decided to wildcat it. I liked the idea of Berger's .284" 180VLD at RUM velocities, so I called Walt Berger. Walt asked about the twist & expected velocity. I heard him say, "Wait a minute, I think I have some of the data from the 6.5mm project around here somewhere...." Several minutes later, he get back on the phone, did some calculations, & said "Yep, that's awful close. They may come apart, and they may not." He explained exactly what was posted above - super high RPMs & the thin J-4 jacket aren't real conducive to rough throats or sharp rifling.

Being a true gentleman, he recommended I speak to Jimmie Knox &/or Bob Cauterucio since both used Sierra-thickness jackets in their bullets. Both fellas also proved to be wise, fine, patient gents & helped out a loony nobody with a theory. The rest isn't exactly history, but a Cauterucio 156 or 176 will definitely hold up to RUM speed. I still shoot Berger 70s & 80s in .223, as much for loyalty to good people as the quality they hold.

I was spotting for a buddy in an F-class match a couple of years ago. He was shooting a 22-250AI & some J-4 jacketed bullets. All was going well - 10, X, X, X, 10.... then POOOF about 200 yards out. I was on the scope & saw it happen. The guy spotting to my left saw it happen also, looked over with a smile, and motioned to my pal to say, "Does he know?" I shook my head (sadistically) & waited. John finally looked over & said, "Call for a mark!" I told him I would, but he wouldn't like the result, because what was LEFT of his bullet was somewhere between us & the 300 yard line. [img]/ubbthreads/images/graemlins/grin.gif[/img]

Sorry for the long post, but I figured from the tone of your post you could use a little humor, plus a reminder that whatever mistakes we make along the way, rest assured some other shooter(s) has done the same. [img]/ubbthreads/images/graemlins/wink.gif[/img]

[BountyHunter]

Recommend couple things.

1. Go with JLk 210s or the new Sierra 210 or Clinch River 216s

2. Borescope the bore, friend had almost new barrel that developed occlusion (ie pit)and was blowing up bullets after it got hot. Not the barrel mftrs fault, it was just under the bore surface and little bit of firing opened it up.

BH

[bsb]

You guys are a huge help, thanks so much I will keep you posted what walt says.