Heavy bolt lift???

[wisconsinteacher]

Hey guys, I am stuck and need some help. The rifle is a 6BR on a Savage action. I used go/no-go gauges to set the headspace on the Criterion barrel. I am using virgin Lapua brass with 29gr of Varget and 107 Sierra bullets with CCI 450 primers. I have the bullets .012 into the lands.

Before I loaded the ammo, I ran the virgin brass through the rifle and the bolt closed with ease. When I fired the ammo, I got a heavy bolt lift but the primers are not flat, they look like new primers except for the primer strike in the middle. I took 5 fired pieces and tried to chamber them, but they do not chamber unless I took a hammer to the bolt.(I did not do that) I then sized them in a Redding die in a Lee press with a Lee shell holder. I started at 1/4 turn out all the way to touching the shell holder and the brass will still not chamber.

So my two questions are, why the heavy bolt lift and what do I need to do in order to get the fired brass sized so it fits in the chamber?

 

[Toby Bradshaw]

Start by collecting some precise measurements with a caliper and shoulder bump gauge (for overall length and base-to-datum proxy) and a micrometer (case diameter above the extractor groove). Compare virgin, fired, and resized brass and report back.

 

[GSPV]

To add information, Matt built this using a prefit barrel. He set the headspace using a go guage.

I'm thinking that the chamber and die don't match. Could be the chamber being too small, the die too large or the headspace set too tight when setting up the prefit.

 

[dkhunt14]

If the reamer that chambered the barrel is to tight you will end up with this. Headspace may do it too. I would have the headspace checked to make sure it is right. Did you ever use that die for another gun to know that it worked. Seen a run of dies get marked the wrong thing. They weren't Dashers like the die said. Also saw dies that wouldn't size enough without taking metal off the die or shellholder. Matt

 

[Switchbarrel]

Before I loaded the ammo, I ran the virgin brass through the rifle and the bolt closed with ease.

I then sized them in a Redding die in a Lee press with a Lee shell holder. I started at 1/4 turn out all the way to touching the shell holder and the brass will still not chamber.

Besides taking the measurements already mentioned.

Maybe I'm missing what you're saying when you list how you made your die adjustments. Did you try screwing the die down further so the press handle will "cam over" as you reach the bottom of the stroke and the brass is all the way in the die? I noticed when adjusting my dies as you mention, my brass actually grew slightly longer before it was sized down ??? I've never understood how the brass gets sized further when the handle cams over because I/you would think when the shell holder touches the bottom of the die...that's it. But, it does size the brass down more. Try taking one piece of brass, from the point of shell holder to die contact, adjust your die in, say roughly ~45* (1/8th turn) increments measuring headspace if you have the Hornady or Sinclair tool and checking in your chamber each time, see if within a couple die adjustments it should help your brass fit your chamber. The goal being to get it to just fit without overworking/oversizing the brass.

Hope that all makes some sort of sense.

-Rick

 

[dkhunt14]

I reread your post and I now understand the brass got tight on the first firing. Sounds like the load was hot. Now if you have a tight chamber you may not be able to size enough to get them back in the gun. You are probably going to have to alter the die or get a custom die. Did you measure the fired case with a Hornady headspace gauge and how much did you bump the shoulders. If you bumped a thousandth or two and the bolt doesn't close easy. The trim length is too long or the back of the case is not sized enough. Usually when you get the click it is the back of the case. Did you use this die on another gun to see if the die works? Matt

 

[effendude]

Another question: Was the brass hard to extract from the chamber or just hard bolt lift? Unless the headspace was set with an incorrect gauge, the factory brass fitting upon the initial firing indicates a reasonably decent, albeit probably generous chamber. Will the no-go gauge fit in the rifle now? It is also possible that the barrel slipped out of headspace when the barrel nut was tightened.
Scott

 

[wisconsinteacher]

I tested the barrel many times after everything was tight with the gauges and everything worked as hoped.

There are some numbers that I cam up with.

virgin brass-1.158"

Fired brass that will fit-1.160"

Fired brass that will not fit-1.163"

From what I am seeing, I need to trim a touch off the shell holder to get the needed bump.

I am guessing the stiff bolt lift was from rounds that were too hot. I was using 29.0gr of Varget with 107 Sierra bullets .012" into the lands. I guess it is time to back off.

 

[snakepit]

I am guessing the stiff bolt lift was from rounds that were too hot. I was using 29.0gr of Varget with 107 Sierra bullets .012" into the lands. I guess it is time to back off.

When you say back off do you mean your powder load or back off from seating into the lands which also raises your pressures or both?

 

[bheadboy]

I agree you are too hot, I would change one thing at a time, back off the lands to a.010 jump and shoot the same load, or drop 1 gr and leave it in the lands

see what happens.

Bob

 

[dkhunt14]

When you get a sticky bolt on a new case you are pretty hot. New brass is always forgiving and you can shoot hotter then brass that is fired a couple of times. So if the headspace isn't messed up the load was hot. It is possible they need trimmed. The trim length on my Dasher is 1.555 and could be close for his BR. Having bullet in the lands usually doesn't make much more pressure then a jump. Even so you should be able to size them small enough to fit the gun. Tight reamers in the back end can drive you nuts. I didn't see any answers on How much bump from a fired case. Maybe you need to do what switch barrel said. Maybe the press is springing under load. That is why you need to know what the measurement is after firing and how much they are bumped. Matt

 

[wisconsinteacher]

I am going to drop charge weight down first and go from there.

I know every rifle is different, but from what I read about load and development, many shooters use 30+ grains of Varget.

I was not able to get any bump when I tried earlier today. I will try again when my head clears and I feel better. I caught the crud from someone.

 

[Warren Dean]

Might want to check the depth of the shell holder where the case sits to the top of the holder.

I use a Redding 308 shell holder and I bought a Hornady 308 shell holder for another press. The Hornady measures .010" thicker than the Redding....(the flat cut out area where the case head sits to the top of the shell holder).

I had always figured that the dimensions of shell holders, except the specifically ground (+) or (-) competition shell holders, was standardized, but that doesn't appear to be the case.

Just a thought.

 

[Jeff Conover]

I have a 40 degree shoulder BRX reamer and Dasher dies. I have to polish the chamber body .002 for my dies to resize the case. Pacific tool and die reamer and Forster sizing die. So your problem could be in sizing the body diameter instead of datum length.

 

[cinch29433]

26 grains and into the lands is a good starting load. It seems that a 6br will grow at the base when things get too hot. I trim mine to 1.51 and size them up in a Forster small base die I had made up. Then work up a load. Barrels are different and my fast twist barrel will weld the bolt closed with 85 grain Bergers and 29.5 grains. I wouldn't try anything close to that with a 107 in that gun.

The other thing is how did it shoot? I have a new barrel that I got from a forum member that will shoot great with a lighter load and jammed. Put a heavy load and jam it and it will get horizontal. I would start lite and try different load lengths until you find something that starts to shoot then turn up the fire.

Good luck!!

 

[22BRGUY]

Might want to check the depth of the shell holder where the case sits to the top of the holder.

I use a Redding 308 shell holder and I bought a Hornady 308 shell holder for another press. The Hornady measures .010" thicker than the Redding....(the flat cut out area where the case head sits to the top of the shell holder).

I had always figured that the dimensions of shell holders, except the specifically ground (+) or (-) competition shell holders, was standardized, but that doesn't appear to be the case.

Just a thought.

I tested the barrel many times after everything was tight with the gauges and everything worked as hoped.

There are some numbers that I cam up with.

virgin brass-1.158"

Fired brass that will fit-1.160"

Fired brass that will not fit-1.163"

From what I am seeing, I need to trim a touch off the shell holder to get the needed bump.

I am guessing the stiff bolt lift was from rounds that were too hot. I was using 29.0gr of Varget with 107 Sierra bullets .012" into the lands. I guess it is time to back off.

It sounds as though your shellholder may need to get ground down somewhat. I've had to do that with a couple of different dies myself. I just took it out to the benchgrinder in the garage and took some off of the face however I know a machinist friend that will do one for me a lot better and nicer as soon as i pick one up to give him. The one I did worked well enough but it bothers me that it may be out of square but the dies do not touch the shellholder face at all right now. If you need to go with a small base die it may make a difference and you may want more precision.

 

[dkhunt14]

I have a 40 degree shoulder BRX reamer and Dasher dies. I have to polish the chamber body .002 for my dies to resize the case. Pacific tool and die reamer and Forster sizing die. So your problem could be in sizing the body diameter instead of datum length.

That's because the reamer is too tight at the .200 line. Matt

 

[spclark]

I had always figured that the dimensions of shell holders... was standardized, but that doesn't appear to be the case

Oh my no, not hardly! Certainly not between brands, sometimes not even in the same brand for holders manufactured a few months or years apart.

A few years ago I thought I was being smart & doing myself a favor buying two or three shell holders for the cartridges I shoot. I'd found it all too easy to lose one somehow, just at the time I wanted to start prepping brass.

Then I began wondering why I was getting variations in case dimensions after very careful set-up. Finally dawned on me switching shell holders adds a variable that's best avoided.

So now all my 'critical' shell holders get stored in a clearly labeled Berger bullet box on the shelf above my presses, removed only for use & immediately replaced.

 

[Rustystud]

Couple of questions:

1. Is the bolt lift heavy without case in chamber?

2. Is the bolt lift get harder and harder as the bolt is lifted?

3. Take bolt out of acrtion, push cocking piece pin off shelf. Does the cocking piece pin bottom out on cocking ramp or rest .020" to .040" off the bottom of the ramp"? If it is slam to the bottom of the cocking ramp it is not adjusted correctly. While the cocking piece pin is off the cocking shelf see if there is a bur at the ramp shelf juncture.

4. Put some Dykem or magic marker on bolt front, bolt face, and back of bolt lugs. Open and close without a case in chamber first. Look for contact points with the barrel tenon. Now insert a fire formed case or Go Gauge and open and close the bolt. Did the bolt face show and wear marks?

5. Take a virgin piece of brass, with Dykem or magic marker mark the web, shoulder and neck of the case. and chamber it, open and close the bolt several times. Check for contact points on the case.

6. Take a fire formed piece of brass and repeat process number 5. Process number 5 and 6 will tell you a lot about your chamber.

7. Bolt timing is very important with Savages. Most Savages from the factory over cock. Often deburring and polishing the trigger hanger, sear, cocking ramp, firing pin, cocking piece and cocking piece sleeve will reduce bolt lift significantly.

8. Pacific Tool and Gauge offers my bolt lift kits and a complete set of instructions on improving Savage bolt lift issues. The bolt lift kit and instructions should reduce your bolt lift by 40-50%. Another advantage with my bolt lift kits it allows for external Firing pin tension adjustment.

Nat Lambeth

 

[ar15topgun]

Nat can work wonders with reducing the amount of effort needed to re-cock a savage bolt. After his magic I can open the bolt on my savage palma 308 tube gun with one finger after firing. Well worth the money spent.