Another raised ring around head

[Teufelhunden]

...Quick test.....
Take one of your 139 Lapuas and insert it into the neck of your fired, unsized necks.
Do they all slide in easily? at least till they hit the donut.
Do some slide in and others resist?
Do none fit back in?
See where I'm going with this?
Just a little play and feel can tell you alot about whats going on in the neck area...

Of the 5 just fired, 2 have an extremely light press fit, and 3 have an almost imperceptible amount of wiggle.

 

[243winxb]

The neck is fine. You dont have a donut, but an area when the collet has not sized. Lee has instruction how to size only part of the neck on there website. http://leeprecision.net/support/index.php?/Knowledgebase/List/Index/13/product-support The body die might have someting to do with it also. A real donut has extra metal, wall thicker in that area. Donuts come from forming one caliber into another. If brass has been fired many times, brass may flow from the shoulder into the neck. The head to datum is measured on the shoulder using a .400" tool. Headspace of the chamber is marked with X & circled in the SAAMI drawing. http://www.saami.org/PubResources/CC_Drawings/Rifle/260%20Remington.pdf ADI makes H4350 for Hodgdon. ADI lists 42.0gr maximum for a 140gr bullet on there website. Different Component = Different Pressure.

 

[Teufelhunden]

Your first photos show a normal chamber situation where there is some radial clearance around the cartridge. Your sizing die is doing the intended by sizing the body sufficiently to freely chamber. The small area just forward of the extractor groove represents the thick brass at the cartridge base and that your chamber pressure was not enough to put into plastic deformation, unlike the thinner body just forward. This is as it should be.

I understand and agree. I'm also starting to think the factory loads ran hot and created an exaggerated ring. 243winxb just brought that up, and somebody might have mentioned it earlier. After running the cases through a round of handloads, the bump rings have turned into not so bumpy. They appear to be less than half the height of the original bumps.

Let's say the ring and the primers are ok until someone convinces me otherwise. What about the stiff bolt lift?

 

[Steve Blair]

Let's say the ring and the primers are ok until someone convinces me otherwise. What about the stiff bolt lift?

[br]
Setback against the bolt face from slightly lubricated cases can produce heavy bolt lift. That may not be the only factor but would certainly contribute. Try wiping some cartridges with acetone or lacquer thinner and see whether the bolt opens easier. Also make sure the chamber is clean.

 

[Teufelhunden]

...ADI makes H4350 for Hodgdon. ADI lists 42.0gr maximum for a 140gr bullet on there website. Different Component = Different Pressure.

I pulled info off the Hodgdon site for the 142SMK since they don't list for the Lapua 139. Probably not the brightest move. Does anyone list a definitive high/low range for the 139scenar?

 

[243winxb]

Lapua Loading Data

Different powder with that bullet. No help for H4350 http://www.lapua.com/view_reload_tables.php?relodata=5&relocaliber=55&lang=en&siteid=products

 

[Steve Blair]

I pulled info off the Hodgdon site for the 142SMK since they don't list for the Lapua 139. Probably not the brightest move. Does anyone list a definitive high/low range for the 139scenar?

[br]
The Scenar tends to be a little smaller in diameter and the data should be fine regarding pressure. If anything, slightly under.

 

[Bulseyetom]

Let me start off with I have no experience with a Savage bolt whatsoever so take this with a grain or two of salt, but my first venture into 100 yard benchrest with a used 6ppc resulted in belted ppc cases very similar to what you have pictured. I think Boyd has hit it on the head when he talks of the excessive clearance between the bolt head and the barrel. Being very new to Benchrest Shooting at the time I had no idea what I was doing wrong. I was surrounded at every match by numerous gunsmiths who were very good at building precision rifles and one of them looked at my cases and said immediately that I had excessive "gap space" and proceeded to tell me how to measure it. It seems most benchrest rifles are built with about .003 clearance between the bolt and the end of the barrel as I remember. Hunting rifles are typically .005 in custom rifles I think. Anyway, he told me to put a piece of scotch tape on the end of the lug and close the bolt. Then keep adding tape until the bolt gets snug. I don't recall the exact thickness of the tape but .015 comes to mind. Any more than a few pieces of tape indicate a dangerous condition even though the headspace is perfect. I put on something like a dozen pieces of tape and then retired the barrel! That solved my problem when the new barrel was properly installed. Tom

 

[Teufelhunden]

Let me start off with I have no experience with a Savage bolt whatsoever so take this with a grain or two of salt, but my first venture into 100 yard benchrest with a used 6ppc resulted in belted ppc cases very similar to what you have pictured. I think Boyd has hit it on the head when he talks of the excessive clearance between the bolt head and the barrel. Being very new to Benchrest Shooting at the time I had no idea what I was doing wrong. I was surrounded at every match by numerous gunsmiths who were very good at building precision rifles and one of them looked at my cases and said immediately that I had excessive "gap space" and proceeded to tell me how to measure it. It seems most benchrest rifles are built with about .003 clearance between the bolt and the end of the barrel as I remember. Hunting rifles are typically .005 in custom rifles I think. Anyway, he told me to put a piece of scotch tape on the end of the lug and close the bolt. Then keep adding tape until the bolt gets snug. I don't recall the exact thickness of the tape but .015 comes to mind. Any more than a few pieces of tape indicate a dangerous condition even though the headspace is perfect. I put on something like a dozen pieces of tape and then retired the barrel! That solved my problem when the new barrel was properly installed. Tom

This was a major concern from several experts early on. I checked the bolt-stub clearance and it checks out spec wise for the floating bolt head that Savage uses.

I then posted a more complete description of the ring. It's not a belt as such. It tends to catch a fingernail going from stern to stem, and does so smoothly. Boyd explained it's a fairly common occurrence for some expansion at this point with factory cut chambers. A hot load could expand the web area to .002"+ as mine have done. This may be a concern if shooting hot reloads using the same brass were to continue. In my situation, the brass appears to be calming down after the first reload. The bump is far less bumpy.

I had a chance in the last few weeks to look at a few cases that had developed a belt as you describe. Exactly the same spot in the case is affected, but the type of damage is quite different.

How about this. Yesterday afternoon I loaded one round. Everything was kept identical except I lowered the charge weight to 42.0gr, and cleaned the brass and chamber with solvent, drying thoroughly, before shooting.

Result was flattened primer with stiff bolt lift.

I'm starting to think neck to chamber clearance may be a problem. A search brought up thick neck walls on the Lapua .260 brass.

Any thoughts from anyone on the next step? Should I buy a bag of Remington brass and see how that acts? Should I consider neck turning? If neck turning, would I need to make a chamber cast first, or do the fired case dimensions tell us enough?

Any other ideas?

 

[Steve Blair]

I'm starting to think neck to chamber clearance may be a problem. A search brought up thick neck walls on the Lapua .260 brass.

[br]
Neck clearance is an easy check. Measure the neck diameter of a loaded round versus a fired case. There should be at least .002-.003" difference.

 

[243winxb]

OP did measure-

I just measured necks using a caliper. Sized brass = .298", loaded brass = .299", fired and unsized brass = .300". Does this tell you anything?

Use a micrometer to measure. With spring back of the brass, i would guess its ok. Could turn a few necks, see if it fixes the hard bolt lift. There is another thread on here with hard bolt lift. Might be the web area of chamber and brass is to tight??

I'm starting to think neck to chamber clearance may be a problem. A search brought up thick neck walls on the Lapua .260 brass.

[br]
Neck clearance is an easy check. Measure the neck diameter of a loaded round versus a fired case. There should be at least .002-.003" difference.

 

[Steve Blair]

Yes, you're right. It is a little tight but should not be the problem.

 

[Teufelhunden]

[br]
Neck clearance is an easy check. Measure the neck diameter of a loaded round versus a fired case. There should be at least .002-.003" difference.

I think I'm getting a system going with a set of digital calipers that can tell us something.

I just now spent some more time measuring cases and again came up with a .001" difference.

Yes, you're right. It is a little tight but should not be the problem.

If it's safe to assume the minimal amount of clearance is not an issue here, then what would the next step be?

Just out of curiosity, does anybody have the neck thickness of Remington .260 brass handy?

 

[243winxb]

I just now spent some more time measuring cases and again came up with a .001" difference.

With a little springback of the fired brass, there is not a whole lot of clearence. Try neck turning or different brass to be safe. See if thinner necks fix the problem.

 

[Teufelhunden]

Sorry it took so long to get back to this, but some progress has been made.

First, I agree with everyone stressing the need in using the right tool for the job. My need for proper tools is without question for reasons of safety and efficiency. I think I like this sport enough to invest in the near future. But, right now I'm doing the best I can with what I have. Onward!

I bought a bag of Win brass and after some inspection came up with a loaded neck approximately .002" smaller than the loaded Lapua stuff.

I loaded and fired a test shot. No stiff bolt lift. I loaded 20 more. All of them smooth as silk upon extraction!

I'll have to learn how to turn necks after the winbrass gets worn out.

I did a quick OCW, but it appears there were neck tension problems using the Lee Collet die. Is it possible the necks are too thin for the die to fully compress the neck against the mandrel?? I need to look at it some more, but I'll use a FL sizer to do the necks in the meantime.

Thanks for everyone's help, and patience!

I know shooting for group size isn't the purpose of OCW, but I hope this isn't just random luck...

 

[243winxb]

Lee Collet Die, i never used one. Lee's FAQ can be helpful. http://leeprecision.net/support/index.php?/Knowledgebase/List/Index/13/product-support Good to know it was a tight neck problem.

 

[BoydAllen]

Winchester brass may have more spring back from the central mandrel that the Lee collet fingers press it against. Chuck up the mandrel in a drill, wrap some wet and dry 320 grit around it and give it a spin, reducing the diameter in the area that the neck is on when sizing by .001 or more, checking sizing as you go. That will solve your problem.

 

[LongRanger]

Devil Hound asked: Lee Collet die. Is it possible the necks are too thin for the die to fully compress the neck against the mandrel?

I love the Lee collet die but.........

I have written elsewhere on these forums that I don't use the Lee Collet die MANDREL. It seemed to be just a little too fussy to set up each time (back before I bought a turret press).

I said the heck with the mandrel and tossed it. Then I carefully adjusted die height with an empty case in the shell holder and a rubber O ring under the center adjusting stem. I found a point where, with the die locket down with no o ring under the die body, there was still enough "cushion" provided by the rubber washer under the adjusting stem to, within 1/4 turn of the stem, go from not squeezing the neck at all to sizing the neck 006 and more under loaded round diameter.

Necks come out 001 and less in runout. AND....an even bigger, huge benefit is that I NOW HAVE AN ADJUSTABLE NECK SIZING DIE!! Now I have an easy way to compensate for variations in bullet seating pressure. (You'll figure it out). Yippee!

Try it.

Just note....when you've reached the point where the die starts to squeeze the neck, it take a barely perceptable turning of the adjusting stem to get another .001 smaller neck dia.

Frank B.

N.B. I have modified this post from the original. Boyd and I must have been posting at the same time. He beat me and what I had written could have looked like I was disagreeing with him.

 

[Teufelhunden]

Lee Collet Die, i never used one. Lee's FAQ can be helpful. http://leeprecision.net/support/index.php?/Knowledgebase/List/Index/13/product-support Good to know it was a tight neck problem.

I went there and they say to apply more pressure to the press handle. I maxed it out and got a bit tighter necks, but some still come out too loose.

Winchester brass may have more spring back from the central mandrel that the Lee collet fingers press it against. Chuck up the mandrel in a drill, wrap some wet and dry 320 grit around it and give it a spin, reducing the diameter in the area that the neck is on when sizing by .001 or more, checking sizing as you go. That will solve your problem.

I think that's the problem and I'll try your solution. I could see having a small collection of mandrels in .001 increments.

Devil Hound asked: Lee Collet die. Is it possible the necks are too thin for the die to fully compress the neck against the mandrel?

I love the Lee collet die but.........

I have written elsewhere on these forums that I don't use the Lee Collet die MANDREL. It seemed to be just a little too fussy to set up each time (back before I bought a turret press).

I said the heck with the mandrel and tossed it. Then I carefully adjusted die height with an empty case in the shell holder and a rubber O ring under the center adjusting stem. I found a point where, with the die locket down with no o ring under the die body, there was still enough "cushion" provided by the rubber washer under the adjusting stem to, within 1/4 turn of the stem, go from not squeezing the neck at all to sizing the neck 006 and more under loaded round diameter.

Necks come out 001 and less in runout. AND....an even bigger, huge benefit is that I NOW HAVE AN ADJUSTABLE NECK SIZING DIE!! Now I have an easy way to compensate for variations in bullet seating pressure. (You'll figure it out). Yippee!

Try it.

Just note....when you've reached the point where the die starts to squeeze the neck, it take a barely perceptable turning of the adjusting stem to get another .001 smaller neck dia.

Frank B.

N.B. I have modified this post from the original. Boyd and I must have been posting at the same time. He beat me and what I had written could have looked like I was disagreeing with him.

Very interesting. I'm going to play with this and see where it goes. Crazy thought, I wonder if a neck collet die designed to be adjustable with a micrometer top would work? I wonder if the Lee could be modified in that fashion?

I didn't regard your post as a disagreement, just another method to achieve the same objective. I'm going to try it and if it works for me I'll add it to my toolbox.

 

[LongRanger]

Teufel....

Be patient as you try the die without the mandrel. It will "feel" different at first but will give amazing flexibility for your efforts.

The center stem of the collet does, in fact, act like a micrometer top. I've made Sharpie index marks on the stem and die body so that I can adjust the amount of squeeze more or less. Am not a mechanical genius, but seems to me that a regular micrometer top would be possible.

My procedure is as follows: I FL size my brass (7 RemMag in this case) then run them over a neck sizing mandrel to "uniform" (hah) them. Then I adjust the collet stem to give just enough squeeze so that a bare bullet will enter the neck of an empty case by hand with slight resistance. Next, I turn the stem about 1/16" or so to increase tension until I cannot push the bullet into the case by hand. I then put the case in my Wilson seater die and seat the bullet with my arbor press, which has a KnM seating force gage attached. If the indicated seating pressure is too much or too little, I adjust the collet stem and try again to get my target pressure. If you don't have a Wilson seater and arbor press, you will do all this by feel just as you do now to set aside those that seated too hard or too easy.

Now comes the fussy part, which may not be worth the while for those not interested in wringing out the last bit of accuracy from their gear.

Use some Sharpie index marks on the collet stem and body to locate the setting which gives the desired pressure. Then start out with the stem adjusted to give you a slightly looser bullet fit than your target pressure. Mark this location also. Test-seat a few more empty cases to assure that none go tighter than your target. These will not all react the same amount when you bring them up to the target pressure, so make some more marks on the stem and body between loose and just right, and note how much pressure each graduation caused.

At this point, I charge my cases with powder and am ready to seat bullets. One by one, starting with the collet stem at a slightly reduced pressure, I seat each bullet. I note the pressure and adjust the stem tighter to give me the desired pressure.

Well, brass is still female and there will be some bullets that require more or less pressure once you get rolling. You can dial up to get more pressure. But pulling the bullet and reseating without putting back into the collet will proly be necessary for those that needed less pressure. I have found that once I find a "safe" stem setting I can expect about 65% of my bullets will be spot on the first time and need no further adjusting.

That's about the full monte of how I use the collet. If you or anyone else try it, let us know your results.

Frank B.