IowaDon and TCR headspace

[Drox]

IowaDon,
Awesome report you produced a few months back pertaining to TCRs and the headspace issue that afflicts them!  Of course, I ask myself where were you some years ago when I first started to reload for my TCR Aristocrat in .223, 243, 7mm mag and .338.  I first noticed the flattened primers, then the cratered primers and, at times, a stuck action.  In fact, in 1989 I reported to T/C having issues with my 7mag.  Their reply to me was they did not recommend shooting reloads, however would consider replacing the barrel just in case there was a quality control issue.  The barrel was replaced, but the problem went on.

I did open some discussion with other reloaders/blogs who had me convinced the problem lie with my poor reloading practices/habits. They absolutely knew cratered primers were definite signs of either low or high pressures. I knew that wasn't the problem, so I continued living with the problem.  Until I saw your dialogue.  Talk about the proverbial hammer hitting the nail on the head!

However, there is still one thing that puzzles me, why is it that all my barrels will shoot factory loads with absolutely NO issue; from the same rifle?  Yet, when I reload my rounds essentially attempting to replicate factory standards, i.e. OAL, case length,  I start to suffer problems.  If I, in my .243 (the worst offender) full length case resize, make sure the case is trimmed to  length and respect overall length (considering the bullet type),  I have problems? 

I hope you can provide some knowledge as I sooooo want to reload for my different barrels!!

Thanks in advance.

[Drox]

I wondering if any tool is made that would measure, with accuracy and precision, the inside of a chamber.  I'm thinking something that looks like a case and micrometer mixed together. This might help me determine the length my cases need to be to ensure lock and proper firing pin strike.

[IOWA DON]

Drox - That your TCR barrels are OK with factory loads but not reloads puzzles me. I think that I have never fired a factory load in any of the rifle barrels for my TCR's. All were handloads or reloads starting with new brass cases. I've fired factory loads from the TCR shotgun barrels and they worked OK but are loaded to a much lower pressure (except one brand of slugs had rims too thick for the action to close sufficiently for the gun to fire. I figured that was an ammo quality problem. I did more investigations on my TCR's since the post on headspace and decided to dedicate certain barrels to certain receivers to best insure good headspace. I can do that since I have five receivers and two or more barrels for each. In summary, the shims for each receiver are as follows: TCR No.1 - Use a 0.005 shim for one custom barrel with a shallow chamber and a 0.010 shim for other barrels dedicated to it, and its factory shim of 0.005 or thinner was apparently lost when it was back for repair. TCR No. 2 - Use a 0.0035 shim for all barrels dedicated to it, and a shim of this thickness was added at the factory either when new or when back for repair. TCR No. 3 - Use a shim of 0.003 for barrels dedicated to it. TCR No. 4 - Use a shim of 0.0075 for barrels dedicated to it. TCR No. 5 - Use no shim for the barrels dedicated to it. Now here is something to show just how loose headspace can be with the TCR's. As I already stated, TCR No.2 originally had a shim of no more than 0.005 and for other barrels, one of which is a factory .223 barrel, I will use a shim of 0.010. That's at least 0.005 thicker than the factory shim, and the hammer will drop on my handloads. Besides that, I full length re-sized previously loaded .223 cases using a Redding Competition Shellholder of +0.010 and the hammer dropped. So between the thicker shim and the increased length of the reloaded cartridge at least 0.015 of headspace was eliminated and the gun still dropped the hammer. With a factory .270 barrel I could only reduce headspace by 0.013. That's pretty sloppy headspace from the factory in my opinion, , especially in a rifle that can flex a little when firing, unlike a bolt action where the locking lugs are closer to the chamber. No wonder cases for larger cartridges do not last a long time in TCR's.

[pdkfishing]

Hello Drox,
I had the same problems, mostly a sticky action with a 30-06 and a 5.56X50R that started life as a 223. When I chronographed both, my handloads were substantially faster.  Since I was using starting-to-medium-range data, I decided that I had very tight chambers/throats; hence higher pressure, even with some starting loads. Experiments with case length and neck turning (worked with the 5.56X50R) and backing off until velocities approximated what I got with factory ammo (worked with the 30-06) made the problems go away. Accuracy improved a bit as well. The 30-06 has since been altered to accept a rimmed case, but I don't think the rimless case had anything to do with the problem. Just my two bits for whatever it's worth. Like you, I got a LOT of good insight from Iowa Don.  I have four receivers and nine barrels, and also dedicate certain barrels to certain recevables. 

[IOWA DON]

pdkfishing - With my .270 barrel I was loading to 3100 fps (130-grain bullets) and getting pretty flat primers and now decided to load to only about 3050 fps to stay a little further from a max load. I've read some factory ammo is only loaded to 2900 fps. One problem with cratered primers in the TCR's is that some of the material from the primers gets caught in the firing pin assembly and eventually the firing pin gets bound up and will not set off the primers. That's why I had a gunsmith build a spanner wrench for me to occasionally take out the firing pin assemblies for cleaning. I think any TCR owner should have one because its a pain sending them back to the factory. My .223 barrel with its original excessive headspace was so bad some shells loaded from new brass would not go off. They slid forward in the chamber enough to cushion the blow from the firing pin. It wasn't much of a problem since I only used that barrel for prairie dogs, but one would sure hate to loose a shot at the biggest buck in the county because of a failure like that. Overall, I think the TCR's work better with smaller cartridges like the .223 and .22 hornet and .17 hornet. Mine give very good accuracy with those cartridges and not so much the flattened primer problems. My two custom 6mm-06 barrels give good accuracy but not as good as the barrels with smaller cartridges. - DON

[Drox]

PDKfishing and Iowa Don,
Thank you for all your insight and experience!  After, I read Iowa Don's initial reply to my message about being puzzled about the problems I was suffering with reloads, I once again began to consider my reloading techniques!  I racked my brain and memory about the experiences I was having.  I recalled using the minimum to almost "middle of the road" loads from the Speer Reloading Manual 12th Edition for the .243 (the worst offender). Sure enough flattened primers and cratered primers.  I was afraid of going any lower in the powder charge for fear of detonation, so I stopped.  However, as I recall I also had some instances where the firing pin did not fire the round; merely dented the primer. ?  Was the chamber longer than the full length resized round and was being pushed by the firing pin?

Well, along comes PDKfishing with his experiences and restores my faith in reloading!  However, after reading PKDfishing's experiences now I'm thinking all my measurements were for the outside of the case.  Never did I consider "inside" the case measurements.  More specifically, the inside of the neck.  I guess I didn't consider the inside of the case as these were once shot brass cases. 

So where does this leave me?  I guess I would sure like to know the true dimensions of my chambers.  How long?  True diameters?  Distance from case neck to landings?  How would I get there?  Trial and error?  Only neck resize and ream the inside of the case necks to where they barely hold the bullet with a friction fit just in case I have a small diameter throat? 

What do you all suggest?

Of course, I could continue to shoot factory loads and ever look back, but where's the fun it that! 


Once again thank you for sharing and helping!!!

[pdkfishing]

Hello Drox,  Based on your last post, it seems to me that you have a headspace problem. Have you tried frireforming with a moderate charge and a crush fit, with the bullet seated out to touch the lands (done by trial and error; with the bullet seated progressively deeper until your rifle locks up just enough to fire), and then neck sizing only? I think Iowa Don does essentially the same thing with shell holders that don't set the shoulder quite as far back. I guess I did that without thinking about it with the 5.6X50R. I try to headspace on the shoulder, even though with rimmed cases and only rarely full-length size anything. Then I turned the neck down from the outside; again, trial and error, until the problem went away. Could have saved myself some trouble by making a cerrosafe casting of the chamber to get the true dimensions of the chamber and throat. Did that later. Turns out, the chamber was a tad long and the neck a bit tight. Sometimes these little rifles are aggravating, but they sure are pretty. 
 

[IOWA DON]

A chamber cast would tell a lot about whether you have a barrel with a tight neck, there is an easy way to verify the chamber neck is not tight. Simply see if a bullet will fit in the neck of a fired case. I have a TCR barrel in .220 Weatherby Rocket that JDG Handcannons made for me a long time ago. It has a tight neck and there is no way a loaded round will fit in the chamber unless a lot of material is taken from the necks by outside neck turning.  I guess they thought I wanted a chamber like the bench rest shooters use.


I also had custom brass cases made by Rocky Mountain Cartridge for one of my 20-gauge slug barrels. They were made based on a chamber cast and a sample 0.622-inch diameter bullet I sent them and the neck area is tight but very precise and not overly tight. I can reload those cases without even resizing. The necks expand enough to release the 720-grain bullets but spring back to there original diameter  as the tight chamber does not allow the brass to expand beyond the elastic limit.


I got the Redding shellholders recently but really needed them for a long time for my .223 and .270 barrels. I have not experimented with them on my 6MM-06 barrels but think they were chambered pretty shallow as I was there when the gunsmith chambered them. He gradually reamed the chambers until they would close enough on a primed brass to fire. However, its probably worthwhile to see if they help. And these barrels get good velocities. The 26-inch fast-twist barrel gives 3250 fps with 105-grain Berger VLD's and the 29-inch slow-twist barrel gives 3900 fps with Nosler 70-grain Balistic Tips. I did load them a little faster but decided to back off a half grain on powder.


I have a .22 Cooper Centerfire Magnum barrel which I ordered from the old TC Custom shop. That's the cartridge that looks like a .22 RF Magnum, but it's centerfire and reloadable. It was initially not chambered deep enough for the gun to close with a loaded chamber, so I returned it and they bored the chamber a deeper, probably excessively, but it at least works. They apparently used a chamber reamer with a long throat because using Cooper suggested loads the velocity was way short of what they stated. I had to use a lot more powder to get advertised velocity but there is no sign of excessive pressure.

[Iowa Fox]

I don't have a TCR but I have been at it a long time with the Contenders and Encores, I found that unless you mechanically and accurately measure to the Datm line on the bottle necks you are just quessing. I also found that the Redding dies were the only ones that I had luck with moving the shoulder just where I wanted it.

[Drox]

Gents (I assume),
So I'm beginning to capture I have headspace issues beyond just headaches!  I will soon buy a set of Redding dies.  Are the dies I need just run of the mill dies or a special type; what do I order?  Through this entire discussion, I have found I only wanted one thing from Santa; the true dimensions of my chamber. 

While sitting at home and enjoying the family, I took out some spent cases (fired but not deprimed or sized) and some factory (Winchester) rounds; all from the same box.  Here is what I did:

1. I first tried inserting a fresh unfired loose bullet into the throat of a spent case.  I did slide in but with some resistance.  I'm talking enough resistance where it would hold the bullet and after shaking somewhat violently still stayed in place; other case were just sorta' snug.  I could pull it in and out, but there was resistance. 

2. Measured the overall length of a spent case (2.043) versus the live factory round (2.036).  For a difference of 0.007 inches.  My Speer Ver. 12 manual states 2.045. Why the disparity of .008 inches from factory loaded to the Manual?  Is there really that much slop in manufacturing standards? If given my spent case measurement, and reloading to a case length of 2.045, and know there is some stretch, would this not case difficulty in bullet release at discharge? Causing higher pressures, and in turn flattened and cratered primers? Humm!

3. Measured the od of the throat of the spent case (0.278) versus the live factory round (0.273). For a difference of 0.005.  The Manual states 0.2760.

4. Measured the od of base of the body of the spent case (0.4693) versus the live factory round (0.4639).  For a difference of 0.0054.  The Manual states 0.4709.

5. Measured the od of the rim of the body of the spent case (0.4668) versus the live factory round (0.4670). For a difference of 0.0002.  The Manual states 0.4570.

6. And finally, measured the od of the shoulder of the body of the spent case (0.4551) versus the live factory round (0.4489). For a difference of 0.0062.  The Manual states 0.4540.

So what?  I don't know!  From these measurements, I would say that there has been more deformation in length than in diameter.  As I am not able to measure the distances to the datum line as Iowa Fox suggests, I can't really tell if the shoulder is been blown out or if the neck brass is just running forward to account for the 0.007 inches in length.

Well, there it is!  Any ideas?  Is there any tool on the market that would measure from my breach face to the datum and still allow for lock up?

By the way, Happy Holidays!

[Iowa Fox]

Drox, I use the Stoney point Headspace Bushing kit. I think Hornady mades it now which is five bushings and a comparator used with calipers. I don't think that a single die set will or I should say can give you the sizing results we are looking for. I found myself so determined to make my TC bottleneck chambered barrels shoot well that I literally went die poor but the results of a well shooting barrel have been worth the effort and expendature. The 223 gets the most use here where I live so it has had the greatest focus and most dies purchased. On that one I use
Redding shoulder bump
Redding Type S bushing neck sizer - same as above but has bushing
Redding Type S full length sizer
2 die set full length
competition shell holder
Wilson arbor press seater
Lee collet neck sizer
Lee factory crimp die.
 
Your fired case should be a pretty close fit of your chamber with a little added length for frame stretch. When I start sizing a caes down I try for a fit that gives about .001 to .0015 clearance between the head of the case and the breach block. The TC break opens need just a little clearance for best accuracy and function. Thats why the datum line is so important on these. Don't worry if the sized case protrudes beyond the end of the barrel a little. As the clearance increases, cases slide further into the barrel and every thing starts to go to heck. For case aol to trim to I use the little buttons Sinclair sells to find out how the chamber was cut, most are much more generous than spec. That is unless you are shooting a custom like a Bullberry. I'm for sure not trying to tell anyone what equipment to buy or how to do it but rather some of the things that I discovered to get me where I wanted to be with accuracy and functional reliability with these things. Every differnt power level of loading will strech and expand the case differently in these things so the dies have to be set up accordingly. On some loads I just use the shoulder bump die followed by the Lee neck sizer. About every 3 or 4 loadings I do anneal necks into the shoulder. The largest cartridge I have for the Encore is a 30/06. My only belted is in a Rem 700 but I'm almost to old to shoot it anymore. Hope some of this helps and is not written in a confusing manner.   

[IOWA DON]

I think the "frame stretch" Iowa Fox talked about is a big variable. With the larger diameter cartridges like the '06 loaded hot it is a big deal but with a .223 loaded mild it's a lot less. I full length re-size everything now as a long time ago I found that even mild loaded, neck sized .223 cartridges eventually got too long for the action to close completely.


Case life has been short for larger cartridges. I just toss the brass after the third loading to be sure the cases don't separate, but maybe I can get more loadings with the bench rest shell holders. The brass for the .17 Hornet barrels seems to last a long time but the chambers are tight, they are not loaded to a high pressure, and are so small there must be little frame stretch. The eventual problem is neck splitting but I started annealing necks for that.


I checked, and a bullet easily goes back into empty cartridges fired two 6MM-06 barrels and my .270 barrel. Same for my .338-.378 bolt action with barrel installed and chambered by Shilen. However, for my 7MM STW bolt action with barrel installed and chambered by Shilen, a bullet will not go back into the case, but since the cartridges are not difficult to chamber, I think the neck is not overly tight.


I had a 700 Remington in .17 Remington with a factory chamber with a short neck. It was way too short to fire a factory round but not a problem for a handloader as I just shortened the necks a bunch. A friend had a Remington 788 in .22-250 with a tight neck. He had a hard time chambering cartridges of one manufacturer's brass but solved the problem by switching brass to a different manufacturer.

[Drox]

Gents,
Thanks for all the information!  If there is anything to take away from this thread is that owning and reloading for TCRs is not for the faint of heart.  In fact, it is for a person who dearly loves the hobby and enjoys "getting their hands wet."  I love it! 

The opportunity you all have provided me to participate in such a knowledgeable and technical conversation is well appreciated.  As I only have one receiver, several barrels and not enough spare cash to purchase additional receivers, I believe the answer to my dilemma is to carefully understand the requirements of each individual barrel relative to my one receiver.  Knowing each barrel's limitations will help me apply the unique reloading practices each barrel requires.

It would also appear each of you are "people before your time" as the concern over headspace in breakopen actions is just starting to heat up!  If you have not already viewed this site (I just found it this morning), please do so:  http://www.bellmtcs.com/store/index.php?cid=242  Make sure you view all hyperlinks and the Youtube video.

Thanks,