Hard Bolt Lift

[Jayhawker]

Your posts certainly came at the right time. I've been working on the idea that I have not been pushing the shoulder back enough. Despite the idea of the "traditional" .001"-.002", my bolt opening and closing felt much better with pushing it back .003" or even .0035". Whether pushing the shoulder back a bit farther will affect the difficulty opening the bolt after firing has yet to be determined.

I'm using a Redding FL bushing die which can be used as a body die. At this point, the press is camming over to get the shoulder pushed back .003". If I go ahead and take a couple of thousandths off the top of the shell holder, will I not be pushing the shoulder back even farther?

 

[BoydAllen]

If you check all of your cases, and they have at least .001 bump that is enough. Bump can vary because of difference in brass hardness, how much lube is applied, and dwell time at the top of the stroke, but once you have clearance, you have clearance. Also, your cases chamber easily, after you fire them the pressure will have moved the shoulder back to the chamber and then there will be some spring back. Increasing shoulder bump will do two things, neither of which is desirable. I will make cases need to be trimmed more often, and it will eventually cause cases to separate just in front of the solid head. For these reasons, particularly the last one, I suggest that you abandon your experiment. On the other hand I have something that you can do to evaluate your Fl die in another way. Measure the shoulder diameter of your fired and sized cases, and do the same thing about .3 up from the case head, on a case that has had its shoulder bumped .001. Friends who had custom barreled 6BRs built found that their stock Redding FL dies were too big, and did not size the back of the case, with the correct amount of shoulder bump. If you see some change in diameter from sizing, you do not have the same problem, but it is worth checking. If you are a little handy with tools, I suggest that you do the modification that I posted the link to. I think that the time and cost will be minimal.

 

[Keith Glasscock]

Or you can buy a lift kit from Stockade or any of the other Savage aftermarket providers. No difference in function, just in frustration if you aren't too handy making small metal parts.

 

[Jayhawker]

Boyd:

By the time I read your post this AM, I had already called Redding on my die. He had me go through a series of measurements including the ones you gave me and felt that the die was OK. One thing he did mention was the fact that some 'smiths are using pre-SAAMI measurement reamers. The older ones measured 1.550" and the new ones are 1.570". If, indeed my 'smith was using the older reamer, he said that this could create a high pressure situation since I trim cases to 1.555". I will try loading some cases trimmed to 1.540" and see what happens. I'm also contemplating a cerrosafe casting of the chamber for a 'smith to look at.

Busdriver: Thanks for the suggestion. I'm all for the easiest way to reach the same outcome and $7.50 is pretty much a no-lose deal.

Thank you both for your input.

 

[4xforfun]

Not one reply on trying to reduce the loads??? I had a Dasher that showed PSI issues at 30 grains with the 105 berger!!

Try some reduced loads...just a couple... at say 29 and 28 gr.....just to see. Just shoot them out the back door or something and see how the bolt lift is.

Just my .02,
Tod

 

[Jayhawker]

I'll do that, Todd. I'm up for any suggestions. I've always tried to maintain as high a velocity as I can to beat the wind we have.

 

[queen_stick]

I think that this will solve most of your problem. Note: the measurement that he shows is the wrong one. The difference in sleeve position with the mod installed is just the rim thickness plus the amount that the ball stick up above the rim. the rest of the thickness goes inside the sleeve. I have seen this fix on several web sites. Reduction in cocking effort is reported as high as 40%. I am going to do mine tomorrow.
http://www.snipercentral.com/forums/viewtopic.php?t=30640

Boyd, I did that... and can say that it's the best 'upgrade' I've ever done on a savage... works great!

4xforfun... I was thinking that earlier in this thread. That might be all it is.

 

[BoydAllen]

Just finished the case head and ball bearing mod. I chucked the case in a cordless drill, with the rim and enough of the case sticking out, to allow for the cut and keep clear of the chuck. I used a reinforced cutoff wheel in a variable speed Dremel type tool, laid the drill on its side, and cut the case off just above the solid head. I learned a long time ago that the direction of rotation throws really fine brass (or what ever you are cutting) dust in your face, so I wore eye protection and a paper mask. After touching the cut up by dragging the part on a file, laid on the table, I installed it with the 5/32 ball bearing. I decided that since the bearing is trapped, that I would skip gluing it in the primer pocket. It helped the bolt lift some. I already had everything but the bearing, which I purchased a half dozen of, for 25 cents each.. saving the other five just in case a friend wants to do his bolt.

 

[rain164845]

The ball bearing mod is exactly what I was going to suggest.

 

[edlongrange]

Message from Lynn:

"JayHawker

If bumping the shoulder back 0.003 makes the situation better your not sizing the base of the case enough.

If your sizing the base properly 0.001 shoulder bump or 0.003 shoulder bump would feel exactly the same as for as bolt lift is concerned.In your example pushing the shoulder back 0.003 improved the bolt lift because it also sized the base of the case more at the same time.

Also if your problem was with the bolt itself bumping the shoulder and extra 0.002 wouldn't change anything at all.

You can take one hard bolt lift case and simply cut the thing in half then try to extract it.This will let you know that it is not the shoulder as you no longer even have a shoulder.
You can take a second hard bolt lift case and only bump the shoulder 0.001 and then take a file and grind away the base of the case.When I say file the case I mean remove a ton of brass all the way around the base.This is a sacrificial case that will be thrown out and never used again.

What you will see is with 0.001 shoulder set-back and most of the base filed away the case will cycle perfectly.

Call Redding back up on the phone an order a small base die.

If your fighting your bolt your taking longer between shots than you need to.You are twisting the gun more in the bags than should be necessary and your not enjoying your shooting experience as you should be.

Lynn"

 

[Savage99]

The reason for the hard bolt lift is that your load is too hot. Cut the powder charge.

 

[Jayhawker]

I've already loaded-up some smaller charges to try out and I'm going to the range as soon as the weather will cooperate. I've always read that a 30 gr. load was the "gold standard" for 6 BR with a 105 gr. bullet and indeed it has been accurate but I'll be glad to give it up to get rid of a high pressure situation and the tough bolt lift. If it works out, I guess I should pull the 50 rounds I've got made-up.

 

[gilream]

Message from Lynn:

"JayHawker

If bumping the shoulder back 0.003 makes the situation better your not sizing the base of the case enough.

If your sizing the base properly 0.001 shoulder bump or 0.003 shoulder bump would feel exactly the same as for as bolt lift is concerned.In your example pushing the shoulder back 0.003 improved the bolt lift because it also sized the base of the case more at the same time.

Also if your problem was with the bolt itself bumping the shoulder and extra 0.002 wouldn't change anything at all.

You can take one hard bolt lift case and simply cut the thing in half then try to extract it.This will let you know that it is not the shoulder as you no longer even have a shoulder.
You can take a second hard bolt lift case and only bump the shoulder 0.001 and then take a file and grind away the base of the case.When I say file the case I mean remove a ton of brass all the way around the base.This is a sacrificial case that will be thrown out and never used again.

What you will see is with 0.001 shoulder set-back and most of the base filed away the case will cycle perfectly.

Call Redding back up on the phone an order a small base die.

If your fighting your bolt your taking longer between shots than you need to.You are twisting the gun more in the bags than should be necessary and your not enjoying your shooting experience as you should be.

Lynn"

EdLongrange...I have this exact same issue with a Cooper rifle chambered in 22PPC. I use the Redding Competition Neck Die, Redding Competition Seater and a Redding Body Die. If I FL size the case taking the shoulder back .001 the case is still very difficult to chamber if not impossible. I MUST take it down .0035 before the bolt will close with no resistance. You earlier suggested a small base die to Jayhawker. I am not familiar with small base dies and from what I understand about them they size the body of the case much more than a regular FL sizing die. Using a small base die, would I be able to get my .001 shoulder bump and size the back of the case body enough for effortless bolt closing?

I should mention that my cases, both Lapua and Norma, have lots of firings on them.

Are their any other alternatives to the small base die?

Thanks for your help.

 

[BoydAllen]

Harrell's Precision makes a selection of dies for that caliber, each slightly different in base dimension. You send them a well fire formed case, and they give you the die that fits your chamber. I believe that the cost is $75. They are by far the most common die in short range benchrest (I think). Two friends, who ignored my advice, ended up buying twice. The second dies (Harrell's) solved their problem. This is not to say that a Redding small base would not work too, but I like the idea of a custom fit. All of this is why, when I decided to build a 6PPC, I started by buying my own reamer. All of my chambers are the same, and once I had dies that fit, I knew that they would continue to, as I replaced barrels.

 

[Jayhawker]

As usual, the simplest answer was the right one. It was the load. Went to the range and fired 10 each of 28gr, 28.5gr., 29 gr. 29.5 gr. and 30 gr.. There was no change on the lever pull until I went from 29.5 to 30 and then it was very obvious that somewhere between 29.5 gr and 30 gr. of Varget, I was creating high enough pressure to cause the tough bolt lift.

Thanks one and all for your input whether you had the right answer or not. I sure learned a bunch in any case.

 

[BoydAllen]

Just a comment:
I am glad that you found your problem. I guess that it never occurred to me that anyone would just pick a number without running a pressure test, with the specific rifle being loaded for. That is the problem with trying to do this stuff over the internet. I always do a pressure series when switching rifles, barrels, components, or lots of powder.

 

[Jayhawker]

There's no accounting for rank, self-taught amateurs. Typically, I have always done it the right way but this time the rifle shot so well with the first load I tried, I figured I'd better grab it and run. I'll know better next time.

 

[gilream]

Jayhawker...glad to know that you solved the problem. I have a strong suspicion that pressure is probably my issue as well with the Cooper Model 21, 22PPC. I've been loading 28.4 grains of H322 with a Berger 52 grain match bullet and Federal Gold Medal 205M primer. Lapua cases. Velocity runs 3550. After an hour of careful measuring of head space and just above the web this afternoon I am convinced that my Redding body die is doing its job down near the web of the case. I have both Norma and Lapua cases for this rifle. The Norma cases probably have 14 or 15 firings on them with no loose pockets. The oldest lot of Lapua (220 Russian fireformed) have 13 firings and I've never had loose pockets there either. I did have a spit case neck with my least used batch of Lapua last month....puzzling.

Your original post has sparked a lot of good information on this thread and for that i am grateful.

Boyd...I'm almost embarrassed to ask, but would you define your process for pressure testing please? Is hard bolt lift one of the signs? I have reviewed all of my old targets where I worked up slowly all the way from 26 grains of H322 to 28.9 grains where I had an extruded primer. I considered that my pressure point. The hard bolt lift started way back.

 

[BoydAllen]

I ....load at the range, shooting over a chronograph. one shot per charge weight, over flags, on a morning when the wind is easy, onto the same target, taking notes as I go, shooting carefully, using the same point of aim. Often I use the same case. I always FL size every time, taking care to bump the shoulder only .001, and with the bullets loaded a little (.003 or so) shorter than the longest length that I can load to without having the bullet push deeper into the case when I chamber a round. This lenghth by old school benchrest definition is Jam, an noun.) I start well down into the middle of available load data, and for instance for my 6PPC increase the charge by .3 per load. Doing it this way, it is quite apparent when the amount of effort that it takes to open the bolt increases. There can be problems with this approach with very small cases. They may not show up as tight when they are quite a bit too hot. In any case, don't be a chronograph idiot. or try to tell a rifle how much its maximum should be. Listen, and do what it tells you to do. Barrels and chambers have a lot to do with how much pressure a load makes, and what your limits are. When I get to that difference in bolt lift, I record the load, the temperature and humidity, and look over my target for evidence of a likely charge somewhere below that last one. Also, is you get any pressure signs that do not make sense, STOP. Do not keep going. You would be surprised how many shooters look at the evidence, shrug, throw another one in, and pull the trigger, in some cases blowing up their rifle. The reason that I often do this with a single case is that it gives me time to think between shots, and I get some sense of what is happening to the primer pocket.

 

[edlongrange]

Another from Lynn (not me - please do NOT reply to me, just post your reply and Lynn will read it - thanks):

"Jayhawker

I am glad you have your problem solved.

On the 22 PPC with a similar problem you can use the 6ppc small base die.You need to size the base first each time as it will shrink the base but increase the cases overall length.The brass has to go somewhere so it will move the shoulder forward while shrinking down the base.

Lynn

Directly from Redding

Special Small Base Body, Full Length & Type-
Now available in the following calibers for firearms with custom chamberings that are tighter than SAAMI specifications.

Note: For the ultimate shoulder bump control, use these dies with our new Competition Shellholders.

Small Base Body & Full Length Dies
Cartridge

Small Base Body Die
Small Base Full Length

Group 1 $51.60 $63.00
223 Remington 74111 91323
260 Remingtom 74531 N. A.
308 Winchester 74155 91355
30-06 Springfield 74148 N. A.

Group 2 $63.30 $79.80
22 P. P.C. N. A. 91301
6MM P. P.C. 74319 91211
6MM B.R. Remington 74317 91201
6MM/284 Winchester 74414 N. A.
6.5MM/284 NORMA (Win) 74415 N. A.
284 Winchester 74141 N. A.

Small Base Type S - Full Length Dies

77323 223 Remington Small Base Type S Full Die $99.60
77355 308 Winchester Small Base Type S Full Die $99.60
77201 6MM BR Remington Small Base Type S Full Die $99.60
77211 6MM PPC Small Base Type S Full Die $99.60"