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cv73
06-27-2008, 01:53 PM
k&m primer gauge deluxe seating tool , does any one have one and do you think it is worth the money.

degmon
06-27-2008, 02:04 PM
I acquired one with all the other tools, rest, bags, new & fired brass, bullets, etc.(Turnkey operation) when I purchased a used Panda 6PPC. An experienced shooter, who posts here frequently, advised me to remove all "that stuff".....I did as suggested, and have not regretted it. I suppose at some point, its use would provide some interesting numbers.....But then, what to do with them.
To paraphrase someone, "If you want to be successful, watch the successful people and do what they do". In my limited experience I've not seen many in use.

Hope this helps.

Dennis

Larry Elliott
06-27-2008, 02:12 PM
Since primers have a certain tolerance in height, seating them to a given depth even in carefully uniformed pockets could either seat some primers too far and others not far enough into the pocket bottom. The well calibrated thumb is the best gauge, seat the primers until the legs of the anvil bottom. Supposedly there's supposed to be a 0.005" preload on the primer, but my thumb isn't that good by about 0.10". Mostly I can feel when the anvil bottoms though.

Dick Grosbier
06-27-2008, 02:13 PM
I own the K&M tool without the gauge and like it fine. I see no need for the dial indicator.

I do like the sinclair better but its twice as much money.

GS Arizona
06-27-2008, 02:54 PM
I borrowed a K&M tool and gave it careful study. To use it as designed, all the primer pockets should first be made perfectly uniform - OK, fair enough. Then each primer is measured for height and seated to the desired degree of compression. In reality, it still takes a well trained thumb. I decided to stick with my Sinclair tools.

The biggest flaw in almost all tools, including the Sinclair and the K&M is that they rely on a shellholder with an open front end. Look carefully as you seat the primer and you will see that the case actually flexes upward at the open end of the shellholder. You can then measure the tilt in the primer quite easily with an Audette or NECO tool properly set up. In most cases, this is on the order of 0.002" tilt from the high side of the primer to the low side. Now, which side were we compressing to the desired pre-compression?

I set up an old RCBS tabletop tool in an arbor press, dropped a case gauge over the top of the case and applied pressure with the press while seating the primer with the RCBS tool (this is easy if you have 3 hands). The result was a primer that had no tilt, but it's not a practical way to seat primers, it was just a test of concept.

As Creighton Audette said in his articles in PS in 1994-1995, factories support the case from the inside with a rod while priming, this gives very uniform seating pressure all around the primer's circumference and eliminates tilting. That's what I was trying to duplicate with my convaluted setup. By the way, I measured a large number of factory primed cases from 1960, 1962, 1967, 1972 and current, and the primers showed no detectable tilt.

Does this matter? No. This was an attempt to understand the forces involved, nothing more. If you develop a good feel with a good tool (K&M, Sinclair, and some others) and you are very consistent about what you do, you will have done as good a job as need be done or can be done.

LASER
06-27-2008, 03:25 PM
I should not get in this but, my two cents. There is the accuracy and consistancy thing. I suggest you talk to Ken Markle, (Mr. K&M) and some of the 1000 yd guys at Williamsport. Probally the venue is the difference. A body can be too anal about unimportant stuff, but... Who is to say?

Very,very respectfully,
LASER

mikecr
06-27-2008, 08:00 PM
The K&M works great. Just as advertised.
You measure the primer thickness with respect to the primer pocket depth, zero the indicator, and then seat to 2thou crush.
Sounds complicated but you get the hang of it quickly.
You cannot do this by feel..

Dick Wright
06-28-2008, 07:35 PM
in Precision Shooting about fifteen years ago explaining how the K & M primer gauge works and why you need it. The included a letter from Federal recommending the .002" "Crush" to the primer.

The only way to prove anything would be in a tunnel with weighed charges, etc, to maximize uniformity in everything. Since the biggest variable we face is shooting in the wind, we are probably better off practicing that.

If we had matches in a tunnel, I would get mine out and use it again. Glorya and I have one each.

Dick

GS Arizona
06-28-2008, 08:10 PM
Dick, do you by any chance remember the issue? Thanks.

LASER
06-29-2008, 06:23 AM
I borrowed a K&M tool and gave it careful study. To use it as designed, all the primer pockets should first be made perfectly uniform - OK, fair enough. Then each primer is measured for height and seated to the desired degree of compression. In reality, it still takes a well trained thumb. I decided to stick with my Sinclair tools.

The biggest flaw in almost all tools, including the Sinclair and the K&M is that they rely on a shellholder with an open front end. Look carefully as you seat the primer and you will see that the case actually flexes upward at the open end of the shellholder. You can then measure the tilt in the primer quite easily with an Audette or NECO tool properly set up. In most cases, this is on the order of 0.002" tilt from the high side of the primer to the low side. Now, which side were we compressing to the desired pre-compression?

I set up an old RCBS tabletop tool in an arbor press, dropped a case gauge over the top of the case and applied pressure with the press while seating the primer with the RCBS tool (this is easy if you have 3 hands). The result was a primer that had no tilt, but it's not a practical way to seat primers, it was just a test of concept.

As Creighton Audette said in his articles in PS in 1994-1995, factories support the case from the inside with a rod while priming, this gives very uniform seating pressure all around the primer's circumference and eliminates tilting. That's what I was trying to duplicate with my convaluted setup. By the way, I measured a large number of factory primed cases from 1960, 1962, 1967, 1972 and current, and the primers showed no detectable tilt.

Does this matter? No. This was an attempt to understand the forces involved, nothing more. If you develop a good feel with a good tool (K&M, Sinclair, and some others) and you are very consistent about what you do, you will have done as good a job as need be done or can be done.

I am not going to reinvent the man's wheel for him. I will say that you shoudda read the instructions. Each primer and primer pocket are measured with respect to each other. INDIVIDUALLY. Very important piece of information. Like I said earlier why not just ask the man? He is very nice, polite, intelligent, credentialed and will answer the phone. His number is everwhere. He has no internet access by choice. I once told him of comments about one of his products on another site. He smiled. Talk to him and all your questions will be answered.
LASER

LASER
06-29-2008, 07:49 AM
[QUOTE=LASER;425949]I am not going to reinvent the man's wheel for him. I will say that you shoudda read the instructions. Each primer and primer pocket are measured with respect to each other. INDIVIDUALLY. Very important piece of information. Like I said earlier why not just ask the man? He is very nice, polite, intelligent, credentialed and will answer the phone. His number is everwhere. He has no internet access by choice. I once told him of comments about one of his products on another site. He smiled. Talk to him and all your questions will be answered.
LASER[/QUOTE
In my own defense I hit submit by mistake before I previewed, HOWEVER, I just checked.The primer pocket depth IS NOT MEASURED by the K&M tool.
Sorry,
keep up the good work,
LASER

Dick Wright
06-29-2008, 07:57 AM
It was around '92 or '93. I did quite a bit of research for the article and wrote it very poorly.

I was a lot younger and more ambitious then. I had the SAAMI drawings for both primers and primer pockets. I needed those drawings when I started manufacturing the Whitetail Match Prep tools.

I miked quite a number of primers top-to-bottom. Never found a box (100 count) with less than .008" variation in thickness. This with the most popular match primers.

If you put all the information together and think about it some, you will see the need for the tool. We both used them for years. Eventually I got lazy and told myself I could do the same thing by feel. (My PhD is in rationalization.) The gauge tool is really easy to use once you get the idea. Ken walked me thru it enough times till I caught on. My beloved Child Bride (a lovely person not noted for world class coordination) caught on right away and used her's long after I put mine away.

If you call Brennan he can probably direct you to the issue with the article. He's pretty cooperative on things like this.

Dick

craigyboy
06-29-2008, 08:15 AM
Dick, I read your article just a couple of weeks ago in a book I have, I think it is called "benchrest shooing primer book" or similar, it contains lots of extracts from the precision shooting mag over the years. Anyhow I have K & M Guage priming tool, I love it, it is a little slower but it works very well, as said to use it right you need to set the tool up for every primer and every primer pocket depth. To be honest though I now do not set it up every time for each individual seating, I find the tool to be so good that I can feel very well when the primer seats, I have left the guage on though so when I feel the primer just seat I can still apply 0.002 of crush though in my experience of using the tool with fed205m primers variance has never been worse than around 0.002-3, with rem 7 1/2's it was a bit poorer with around 0.005.

German on the note of primer tilt I think the k & m tool works quite well in that respect as the spring under the shellholder holds the case in tension quite well against the rim of the shellholder though I will admit I have never checked to see so I may be wrong.

GS Arizona
06-29-2008, 08:16 AM
Thanks, Dick, will do.

Dick Wright
06-29-2008, 06:23 PM
Thanks. I forgot that the article was also in the "Benchrest Primer".

As regards the tilt of the primer within the pocket... If you have a primer pocket uniformer like the Match Prep tools I used to make, that should not be a problem. It creates a flat plane (the bottom of the primer pocket) that is parallel to the plane of the case head. Squishing the primer down till it is tight against the bottom should level out the top of the primer and make it pretty level with both surfaces. (plane? Plain? ???????)

Incidentally, Russ Haydon sells the Match Prep tools nowdays.

Dick

GS Arizona
06-29-2008, 07:45 PM
I have one of your old tools, Dick - great item! I'll pull out my copy of the BR book and re-read the article. I'll also borrow the tool from my friend again and re-evaluate it, I hate to think I'm missing something here. Thanks to all.