6BR is Siff in Rapid Fire; Resolved.

[matorre]

My gunsmith built me two guns with a new reamer.
One is single shot. It cycles fine and dandy with all loads.

Both Krieger Light Palma barrels

The other is a five shot used to shoot three position.

The Problem..............................
In the rapid fire stage 3 out of 5 cases feel like they have glue on them
and I must yank fiercely on the bolt handle. No signs of pressure.
Random cases, not the same ones, second time around.............

Case loads easily after its been fired.

Even though its new, soak with "Wipe Out" , and "Butches" reapetedly.

Reamed with a no turn neck. Both guns got .001 for head space, but after
trying every easy fix, we sent back in and gave it .0025 head space on the
gauge.
Chamber has been polished. Load has been back down to minimum and back again.
The single shot gun fires max loads fine.
The extractor cam is doing its job.
Bothe R-700 receivers tuned by the same machinist.
Load is new Lapua brass.
CCI450s
Varget. 27.5g to 31gr.
107SMK
Swapped out fireing pin springs, tried Harrells dies, Forster dies,
Redding dies,.....polish,polish,polish.

I'm looosing the will to shoot over this. Been trying to solve to two years.
I would throw more money at it but, where ?
Regards
Michael

 

[hdbiker1]

Re: 6BR is Siff in Rapid Fire

I've got a 700 in .223 that I had built. Every once in a while, a fired case won't extract without either tapping it out with a bore rod or tapping the handle with a block of wood. I was told by Dan Armstrong (Accutig) to remove the firing pin reinsert the bolt and lift the handle to the 3 o'clock position and place a feeler gauge between the bolt handle and the receiver. I came up with .034" clearance (too much). Dan said I only had 30% of my primary extraction. Dan says he tigs the handle to have .010-.015" clearance for maximum primary extraction. This may not be your problem, but worth a check. Remington doesn't usually give you max primary extraction from the get go and then you have tolerance stacking. Then you have your receiver trued and the internal lugs are cleaned up and then your bolt lugs are cleaned up and you've lost even more. I hope you can make heads or tails of what I'm saying. If this is your problem, you need to have your bolt handle moved closer to the receiver.

 

[matorre]

Re: 6BR is Siff in Rapid Fire

Yeah....good point , but I have most of my primary....... have never seen it do it in slow fire............and the bolt is
gluey from the first monument of lift when it does do this.


If it was hanging up at a later point I could overpower it with
momentum, but I have to heave..... at the very start of the stroke.

If you are not expecting it and it catches you by surprise it can
really break your pace.

I disagre with you situation, and the assesment, however.......

Bolt rifles are not supposed to
be sticking cases in them so as to need a Mauser claw extractor and
a hydraulic assist to budge a case.

Are you sure you are not using Federal cases? :- )

Just ask any of the PPC shooters, or stool shooters.
They wouldn't put up with this mayhem.

M-

 

[hdbiker1]

Re: 6BR is Siff in Rapid Fire

You may be right, but primary extraction does serve a very useful purpose, every rifle I know of has it.
No fed brass here, I use Lapua. I have a PT&G bolt in my 6br repeater set up and have no problems. Just out of curiosity, what brass are you using and what is your chamber neck dimension?

 

[matorre]

Re: 6BR is Siff in Rapid Fire

Lapua .....new.
.272
M

 

[dkhunt14]

Re: 6BR is Siff in Rapid Fire

Every barrel is different for pressure. I have had 8 twist Krieger in a Dasher that you couldn't run 32 or Varget in. I have had the same twist Krieger on the same gun that you could run 33.5 or more. It could be that you are too hot or that you are not getting enough size on the one. Are you measuring bump? Are you measuring to see if you are getting any sizing at the .200 line? What is your loaded neck Diameter? Matt

 

[matorre]

Re: 6BR is Siff in Rapid Fire

The Harrells die goes to the .200 line.
I am only getting .0001 or .0002 of stretch after fire.
The minimum load does this too.
Loading below minimum is dangerous.
M-

 

[gme]

Re: 6BR is Siff in Rapid Fire

Is your sizing die resizing the base of the case? If the base is not being sized you will have stickey extraction, happened to me on a BRX I built, I fixed it by grinding the top of a case holder and running the brass through a. 308 die so the base was reduced by .001, problem went away

 

[dkhunt14]

Re: 6BR is Siff in Rapid Fire

If your die doesn't size the case at the base it will be sticky like gme says. If you don't bump the shoulder .001 to.002 you can also get sticky. Matt

 

[Erik Cortina]

Re: 6BR is Siff in Rapid Fire

Good suggestions so far. Try this:
Swap firing pin assemblies between both rifles and see if it improves.

 

[LHSmith]

Re: 6BR is Siff in Rapid Fire

Chamber has been polished.

Depending to what degree of polish, it may have made matters worse....or been the problem all along. I believe P. O. Ackley proved that a mirror polished chamber would cause the very problem you are having.

 

[Eddie Harren]

Re: 6BR is Siff in Rapid Fire

Now Smitty, you know what the "experts" say about that! You better go get your flame suit on.

 

[LHSmith]

Re: 6BR is Siff in Rapid Fire

Eddie... I just keep the suit on now that we have legions of Tacticool experts from SH

 

[matorre]

Re: 6BR is Siff in Rapid Fire

wow , too smooth gets a grip???
Who'd' a think.
How do I " roughen" it ?

PS... this problem reared its head before
I polished, but I want all the ducks in a row.

(P.O. was a critical thinker, I think)

And
I have bench ground my shell holder too, so I am not limited there, either.
I experimented with bumping the shoulder at, 0.0000 to a
wild ( for me ), 0.006.

M

 

[LHSmith]

Re: 6BR is Siff in Rapid Fire

Well, I was going to suggest Google is your friend, but forget that.....too many bad ideas out there. I believe smiths use 320 paper wrapped on a wood holder running the barrel in a lathe. But, you better verify that you haven't over done it already with your polishing.

 

[expiper]

Re: 6BR is Siff in Rapid Fire

Mike,,,if the bbls. will interchange from one action to the other see if the problem exists when you do so or if the problem is just with one action,,,,this is an example of what you get when your "true" an action,,,(lack of extracton and head space issues ) and you had one smith do the acton work and another do the bbls,,,,,you prolly have as much money in em as you would in new Pandas/Bats---since the resize die works with one bbl. I doubt that they are the problem,,,,you are seeing the beauty of having (and the pain of NOT having) brass/dies/chambers that are working in concert,,,it is difficult to get with mis matched parts,,,,keep measureing and good luck,,,Roger

 

[matorre]

Re: 6BR is Siff in Rapid Fire

I made some chamber casts and
also sent some fired cases to Harrells.

No heavy handed use of abrasives here.
FWIW, the chamber is dusted with 320 Emery
paste for about 15 seconds on felt,
and finished with a scotchbright pad for about 10 seconds.

One smith did every bit of work, and one reamer used two times.

Extractor cam has been verified, and works very well. That is really
kind of a basic thing if you are screwing on barrels I believe.

Yeah google is as cracked as their liberal owners.
M-

 

[Tim Singleton]

Re: 6BR is Siff in Rapid Fire

Have you tried a small base die?

 

[John from MN]

Re: 6BR is Siff in Rapid Fire

I'm guessing the problem has something to do with the bolt.

The fact that it works fine for slow fire suggests a binding issue. I hate mysteries like this.

I think Cortina is on the right track.

Will your bolts interchange and still maintain safe headspace?

 

[gme]

Re: 6BR is Siff in Rapid Fire

Just grinding the shell holder is not enough, because in order to reduce the base you would be bumping the shoulder way too far in a 6br die, you also need to run the brass through a. 308 die so only the base is reduced without anything else being touched, measure the base of your fire brass vs your resize brass at the point where the chamber starts, it should be at least .001 difference