K&M Arbor press with Force Measurement and Dial Indicator – tell me more.

[jlow]

I’ve been eyeing this press but at least just looking at it at K&M’s website, I cannot quite figure out how it works. I know that it works like a regular single stage press but my first question is can you use your regular bullet seating die with this press or does it comes with its own seater or is it even a seater?

If so does this mean that the press is only used for testing and not for regular bullet seating and production?

If it can be used for regular round production, how does one adjust seating depth and what is the quality of the product?

I am also puzzled by how it measures seating force. The website talks about the stack of Belleville spring washers and how their deflection moves the push rod and dial indicator – can someone give a more enlightening description?

 

[tclaunch]

In conjunction with an inline seater it is the best tool to see uniform pressures during seating thats out there. I use Redding S-Typed FL dies and this K&M arbor with indicator to seat only.

 

[bozo699]

jlow,
The press is for inline seating only as a general rule, they do make inline neck dies but NO one I know neck sizes, so with that being said it has a dial indicator on it that works via a spring attached to the seatingpress under the actual seating pad so to speak and as you apply pressure the spring gives, resulting in a reading on the indicator, the numbers don't really mean anything, there just for judging how much it takes there is no rock solid scientific answer it is this many pounds it's just a reference number so to speak, you probably could find one in theworking process on you tube.
Wayne.

 

[Steve Blair]

The deflection indicated by the dial could be equated to a force if you knew the spring rate of the belleville washers used in the stack. Bellevilles are constant rate springs that have little "stacking" effect within the normal deflection range. I have one of these arbor presses and find the feature useful to help identify seating force variation.

 

[bozo699]

The deflection indicated by the dial could be equated to a force if you knew the spring rate of the belleville washers used in the stack. Bellevilles are constant rate springs that have little "stacking" effect within the normal deflection range. I have one of these arbor presses and find the feature useful to help identify seating force variation.

Thank you Steve for the correct terminology of the arbor press parts I was struggling trying to come up with something.
Wayne.

 

[jlow]

Thanks for the information guys!

Have not used inline seater die before only threaded seaters thus the confusion. What brand of inline seaters do you guys use in conjunction with the K&M arbor press? Do inline seater dies work by just sitting under the arbor press and having the arbor press down on it i.e. it is not attached to the press like the threaded seater dies?

Wayne, not a problem with not being able to do neck sizing as I have dies to do that already and at least for now no plans to use this at the range. Not worry too much about the actual number from the dial indicator, figure it is just a number for comparison purpose.

 

[Codeman]

Wilson is the most common type of inline seater dies. The die is not attached to the press.

 

[jlow]

Thanks! I learn something new again which is great!

 

[bozo699]

Thanks for the information guys!

Have not used inline seater die before only threaded seaters thus the confusion. What brand of inline seaters do you guys use in conjunction with the K&M arbor press? Do inline seater dies work by just sitting under the arbor press and having the arbor press down on it i.e. it is not attached to the press like the threaded seater dies?

Wayne, not a problem with not being able to do neck sizing as I have dies to do that already and at least for now no plans to use this at the range. Not worry too much about the actual number from the dial indicator, figure it is just a number for comparison purpose.

Spot on jlow, I reread my post and it was not very clear but you understood exactly what I was trying to say.
Wayne.

 

[jlow]

Thanks Wayne as usual. I am going to start a new thread to ask about the inline dies.

 

[hogan]

Although noting a difference between typical & non-typical seating pressure forces might be valuable to recognize, what will impart uniformity of dimension and brass neck seating resistance?

To what degree are you willing to cull brass and bullets in ammunition which assembled outside the norms you establish and can measure?


Were all bullet jackets and brass of uniform composition and consistent metallurgical alloy, perhaps meaningful data could be gleaned. But... Whatcha gonna do? Ream every case's inside neck with every loading to assure bearing surface of bullet to neck is metallurgically consistent? Gonna scrap every load that measures off by so many fractions? Will those bullets seat the same in a new case if they were seated once before?

Perhaps a titanium or carbide bullet dummy used first to assure case neck elasticity and proper tension???

Unless you are shooting a 50# unlimited class gun from a machine rest, does control to this degree and culling loads out of spec really matter or deliver results that can be judged to be significant?

 

[Steve Blair]

Although noting a difference between typical & non-typical seating pressure forces might be valuable to recognize, what will impart uniformity of dimension and brass neck seating resistance?

To what degree are you willing to cull brass and bullets in ammunition which assembled outside the norms you establish and can measure?


Were all bullet jackets and brass of uniform composition and consistent metallurgical alloy, perhaps meaningful data could be gleaned. But... Whatcha gonna do? Ream every case's inside neck with every loading to assure bearing surface of bullet to neck is metallurgically consistent? Gonna scrap every load that measures off by so many fractions? Will those bullets seat the same in a new case if they were seated once before?

Perhaps a titanium or carbide bullet dummy used first to assure case neck elasticity and proper tension???

Unless you are shooting a 50# unlimited class gun from a machine rest, does control to this degree and culling loads out of spec really matter or deliver results that can be judged to be significant?

[br]
Well, I turn necks to ±.0001, anneal, brush inside neck with graphite-laden nylon brush and size with custom dies sized to the neck diameter and desired tension. I do not shoot a 50 lb. unlimited gun but I am trying to maintain ¼ MOA vertical at 1000 yards. What I am generally looking for with the K&M is seating force that is outside the normal range for a given case/bullet combination. When loading a compressed load, it is not useful. At that point, it functions just like any other arbor press. This a not a universal panacea, just another way to reduce variation.

 

[bozo699]

Although noting a difference between typical & non-typical seating pressure forces might be valuable to recognize, what will impart uniformity of dimension and brass neck seating resistance?

To what degree are you willing to cull brass and bullets in ammunition which assembled outside the norms you establish and can measure?


Were all bullet jackets and brass of uniform composition and consistent metallurgical alloy, perhaps meaningful data could be gleaned. But... Whatcha gonna do? Ream every case's inside neck with every loading to assure bearing surface of bullet to neck is metallurgically consistent? Gonna scrap every load that measures off by so many fractions? Will those bullets seat the same in a new case if they were seated once before?

Perhaps a titanium or carbide bullet dummy used first to assure case neck elasticity and proper tension???

Unless you are shooting a 50# unlimited class gun from a machine rest, does control to this degree and culling loads out of spec really matter or deliver results that can be judged to be significant?

Hogan,
To most of your statement, if you were talking 100-300 bench rest probably not, I have seen guy's win matches with brass I wouldn't use for sighters but in long range shooting every little variable makes a difference and the force it takes to seat a bullet is no different, if it is all over the place so will your bullets on the target as a general rule. I think the biggest mistake we almost ALL make on this forum is the person asking shoots one discipline and the person answering shoots another or from one person to another answering shoots different disciplines and then there is a conflict or debate, I think we could save a lot of time and hassles if we stated what we wanted to do at what distance and give a answer the same but we don't so it continues the only thing the same between short range shooting and long range shooting is we all have to pull a trigger most all the rest of it is a little different.
Wayne.

P.S I only shoot 1000 yards at this time in competition so EVERY LITTLE THING MATTERS to me, someday I may shed all this stress and go to banging steel or something just for the fun of it, once your hobby has become a job to you it takes the fun out if it.

 

[johara1]

Wayne, You can see it at 300 for sure and 500 it really shows up. To get under .600 at 500 yds. you better have very uniform neck tension. You are right it is the sum of all the little thing...... jim

 

[hogan]

Understand about tension and seating by feel; primers anyway. Don't use an arbor press or any straight-line dies...

But really, until you are past the seating process, you don't really know how your brass/bullet combo will tension or register/deflect on your indicator gauges. Is that correct?

I was not denigrating the effort, just acknowledging that if you have to scrap a load, you lose the bullet and the case; or do you reuse bullet and rework the brass trying for correct tension in next batch of loads you do?


Sure, if I was trying to be all I could be at 1000yds, guess I'd cull a lot of components and call it cost of doing business. Make the best ammunition you can assemble and hope your technique and other gear is up to the task.


If you are gearing to make perfect ammunition in every respect you can consider, would like to know what you 1000yd shooters are using for scope mount systems? Is perfect scope alignment or congruence with bore a primary concern? What gear do you use to eliminate variables in this other critical arena?

 

[Steve Blair]

If you are gearing to make perfect ammunition in every respect you can consider, would like to know what you 1000yd shooters are using for scope mount systems? Is perfect scope alignment or congruence with bore a primary concern? What gear do you use to eliminate variables in this other critical arena?

[br]
My F-Open rifles have Stiller Viper SS, BAT 3LL or 3L actions, all with integrally machined Picatinny rails at 20 MOA. The scopes all use Nightforce Ultralight rings and are torqued to 65 lb/in with a Seekonk wrench.

 

[jlow]

Hogan – I think what you are trying to say is that there is a limit to what should and could be done – I am certainly on board with that. For example, using the GemPro 250, if I was weighting 44.1gr of Varget, I set a limit in terms of what I will accept, normally within 0.04gr variability because the scale is generally not that perfect and one can end up chasing one’s tail if one always require the reading is on to the last 0.01gr accuracy. There is also a good basis for setting these limits as say for example when I find the weight is 0.06gr off, I reweight the powder and 9 time out of 10 it is off by 0.02gr and so there is a real problem (as to a perceived problem).

As to the question of culling brass, I follow Glen Zediker’s recommendation of no more than 2 thousands off. Actual experience with this brass in terms of run out has shown that it has worked well with average loaded rounds having average runout of <2 thousands.

I understand the frustration dealing with this. The biggest problem with reloading is that there appears to be a lot of variables that are hard to control and many steps that are meant to improve the final product which does not appear to be well documented. However, the best advice I give to myself is what I normally do when I am troubleshooting a problem in the lab i.e. when there is a problem, it is usually caused by more than one thing and the way to deal with it is to find each one and fix it and see if it fix the problem. This method of whittling down the problems has worked well for me in the research arena for more than 30 years and appears to work for me in reloading, although some frustration persist but of course part of that is because I am a Type A and so some sort of control freak – LOL!

 

[jlow]

Thanks Dave for writing in with lots more useful and interesting detail information. You must also live in MI like me then and close to the lake. I will probably buy a set of these in the near future.

BTW, off topic but I like you idea of marking the extractor groove, I usually mark the primer but that usually cause a transfer to the bolt, not a big deal but your way is better!

The customer seaters is interesting to me but I use a factory chamber and so not a reality for me.

 

[bozo699]

Thanks Dave for writing in with lots more useful and interesting detail information. You must also live in MI like me then and close to the lake. I will probably buy a set of these in the near future.

BTW, off topic but I like you idea of marking the extractor groove, I usually mark the primer but that usually cause a transfer to the bolt, not a big deal but your way is better!

The customer seaters is interesting to me but I use a factory chamber and so not a reality for me.

Yes Dave I agree you had to most complete useful post on the subject, I guess it helps when you have first hand info like that, I have seen where you have wrote a similar post before but the refresher was good, thank you.


jlow,
Not exactly true, remember you mentioned something about different chambers having different dimensions so you didn't buy the better fit theory? well you were right, even with that factory chamber you could benefit with a custom die if the rifle is a shooter anyway, by having a cast made of your chamber and a die made accordingly, it may not be worth the hassle or money for you but it would have it's benefits I think.
Wayne

 

[jlow]

Hi Wayne,

I stand corrected. The gun actually already shoots 10 round sub-MOA already but as a Type A, I would certainly agree that it should be able to do better! Perhaps this is the ticket?