Bumping shoulder back

[tunacan]

I may be a little long winded, but bare with me.

I just put together a sweet little 6.5x47 with a .290" neck.

In every one of my rifles when I bump the shoulder back the bolt cams down effortlessly. I cannot get the 6.5x47 brass to size without a little "bump/hickup" while camming down. I took the firing pin and ejector out so I can get a better feel.

The bolt cams down easy, but there is the slightest bit of resistance. Is this problematic at all? Headspace too short on the chamber?

This is new brass so I know it doesn't need to be annealed.

I have a Redding comp set with a body die and a Forester FL die.

Im no rookie to reloading, but I have never run into this before.

Thanks

 

[BoydAllen]

How much are you bumping, and is this from an established maximum value for that chamber?

 

[tunacan]

I don't have a headspace guage so I was just adjusting my body die until the brass chambered without interruption.

I put the gun together and shot it a to make sure it had potential. I then sent the barrel off to get nitrided and the put it back together.

When I put it back together I went to chamber a previously fired round and it wouldn't even start to cam down.

I bumped the shoulder back just enough so I could close the bolt.

I guess there is always the possibility that I torqued the barrel a little tighter than last time.

 

[BoydAllen]

Perhaps the process that was done to the barrel requires some heavy duty cleaning to bring the chamber back to the same smoothness as before it was treated. Were there any post treatment instructions? I suggest that you get some way to measure bump. The Hornady attachment for calipers works fine. I don't think that how you torqued the barrel would have any effect on this. I put mine on pretty tight and have never had an issue. Reports from shooters who have had their barrels Melonited have indicated that their bores and chambers required quite a bit of work after treatment.

 

[treeman]

take a sharpie or majic marker and paint the out side of a case and chamber it, it will tell you where it is tight.
In the past I have had to take a few thousandths off the top of a shell holder to get enough shoulder bump to chamber smoothly

 

[Webster]

I don't see how it is possible to heat treat the barrel at temperatures around 1000F without causing distorsion. Apparently many people are happy with the results. It would be interesting to see if the same chambering reamer would slip into the chamber after heat treat.

 

[BoydAllen]

I did not mean to imply that the chamber would have been distorted, just that it might have been roughened, and I believe that there is information to that effect that has been published on this forum, by shooters who were pleased with the results of the process, but had to do a much heavier then usual cleaning(of both chamber and bore) with an abrasive, after treatment, as per instructions. As to putting a a chamber reamer in a chamber that had been hardened and was suspected of being roughened in the process, I would think that if it turned out that there was an issue, that the edges of the reamer might be adversely affected.

 

[Dgd6mm]

tunacan,
This rifle, is it a Savage with a barrelnut?

 

[tenring]

First, there is no need to bump the shoulders unless the bolt is difficult to close. This is best measured with a Redding Instant Indicator. I use the same one for 6mmBR and 30BR. With FP removed the bolt should not flop down - if so, that means you went too far. Ideally, you should feel just a tad of resistance when the bolt is about 80% closed. That means the shoulder is beginning to lightly touch in the chamber. Turn your sizer die down in increments of about1/32nd" until you feel that slight resistance. Set your die at that point and keep it there. If you want to neck size thereafter, go to Sinclair and buy a set of Skip Ottos die shims. With a shim under your F/L die, you need never set it again.

 

[tunacan]

The rifle is built on a Rem 700.

I was under the impression that do not want too much resistance when closing the bolt. I will leave it as is and shoot it and go from there

 

[ridgeway]

IMO, a stub or bump gauge is important so you know exactly how much you are bumping. I FL size every time, 6 BR and 6 Dasher. I bump .0015" and this provides a very nice bolt close with no resistance. Nothing is more aggravating when your gun gets upset in the bags from a case shoulder not being bumped enough.

One thing I do to ensure I'm bumping consistent is during my sizing process. When I run a case into the sizer die, I let the ram lock(Forster) in for 2-3 seconds. This will ensure the case makes full contact inside the die. I've seen guys ram a case in and out of a sizer die so fast that the die barely touches the shoulder.

 

[kelbro]

When I run a case into the sizer die, I let the ram lock(Forster) in for 2-3 seconds. This will ensure the case makes full contact inside the die.

I started doing the same after reading that on this site. Seems to add to my consistency.

 

[davidd]

When I run a case into the sizer die, I let the ram lock(Forster) in for 2-3 seconds. This will ensure the case makes full contact inside the die.

I started doing the same after reading that on this site. Seems to add to my consistency.

Same here, run the ram up and then let it dwell at the top of the stroke for 2-3 seconds

 

[kraky]

Interesting idea holding the top of the stroke. I've been known to double pump range brass in the body die to get head space back....will have to try the "hold method"!

 

[fguffey]

I may be a little long winded, but bare with me.

I just put together a sweet little 6.5x47 with a .290" neck.

In every one of my rifles when I bump the shoulder back the bolt cams down effortlessly. I cannot get the 6.5x47 brass to size without a little "bump/hickup" while camming down. I took the firing pin and ejector out so I can get a better feel.

The bolt cams down easy, but there is the slightest bit of resistance. Is this problematic at all? Headspace too short on the chamber?

Posted by: tunacan
« on: 03:46 PM, 04/17/13 »
Insert Quote


I may be a little long winded, but bare with me.

I just put together a sweet little 6.5x47 with a .290" neck.
____________________________________________________________________________________________________________________________________________________________

6.5mm47, case head same and or close to the case head of the 308 W and the 30/06 at .470, that is an advantage to the “I just put together a sweet little 6.5x47 with a .290" neck” builder/reloader/case former. It is not necessary to purchase expensive cases when determining the length of the chamber from the shoulder of the chamber to the face of the bolt, referred to as ‘head space’, when I cut a chamber I form/size cases in different lengths when measured from the shoulder back to the head of the case. I start with short cases for short chambers then finish with cases for long chambers, the shortest case length from the shoulder back to the head of the case is .012- shorter than a minimum length/full length sized case.

The new cases you purchased are new minimum length, after you sized them they became full length sized cases. Your new minimum length cases would not allow the bolt to close without resistance, after sizing your bolt would not close without resistance, meaning your cases are longer from the shoulder of the case to the case head than your chamber. Your chamber is not go-gage length, you need to increase the length of the chamber or shorten the length of the case from the shoulder back to the case head.

I size/form cases for short chambers that are shorten than the chamber by .016”, the full length sizer die, in the perfect world sizes cases that are shorter than the go-gage chamber from .004” to .005” by simply raising the ram when sizing a case to full length size. An additional .012” can be added to to the mount of sizing by adding a feeler gage between the deck of the shell holder and head of the case. And yes, hesitate at the top of the stroke when the ram is raised, or lower the ram slightly then raise the ram again making sure the die contacts the shell holder, if the die does not contact the shell holder the case is not being full length sized to minimum length.

Forming dies, I have forming dies and reamers.

Cases used to determine the length of the chamber from the shoulder of the chamber to the bolt face can be formed from 30/06 and or 308 Winchester, cases used for this purpose allow the reloader/builder/case former to use the cases as tools, there is no rule that says the cases are formed to shoot.

I would suggest you purchase a feeler gage with multiple leafs, I would suggest you insert a leaf that was .002” between the deck of the shell holder and head of the case when full length sizing. If the case offers resistance to bolt closing increase the thickness of the leaf.

F. Guffey

This is new brass so I know it doesn't need to be annealed.

I have a Redding comp set with a body die and a Forester FL die.

Im no rookie to reloading, but I have never run into this before.

Thanks

Then the part about bumping, there are not many dies I do not have,none of my dies are bump dies, all of my dies full length size my cases, if the shoulder is bumped on my cases the case body gets bumped and the neck gets bumped meaning my die progressively sizes the case beginning with the case body, when my cases are sized I have 100% contact between the case and sizer die. I know, there are bump dies, again, the bump die contacts the body of the case then it contacts the shoulder or should I say it contacts part of the shoulder.
Before bump/body dies I had bump/body dies, I used the 30/06 for the 270, I used the 8mm06 for the 30/06, 338.06 for the 8mm06, 308 W for the 7mm08, not a problem but there was the part of the shoulder that ‘was bumped’ forward, something like an unintended do-nut.

 

[limbic]

Have you FL sized the brass yet?