Surprising neck tension test ... (at least it surprised me)

[rustyinbend]

Been screwing around lately with different things that impact neck tension, specifically "Bushing" and "Mandrel" combinations. Took a test out to the range today, and was surprised by the results. This was with a MPA 300-WMBA rifle with maybe 1500 rounds down the barrel. Common elements between the test groups were Lapua 2x brass (annealed), Federal 215 Magnum primers, Berger 200.2x bullets, Retumbo 74.7gn of powder, and seating depth the same (obviously). The ONLY difference between test groups was the Bushing and the Mandrel.

The top-left, center, and top-right of this target is with .335 bushing and .3055 mandrel. Average velocity was 2989 with SD of 8.83 ... and crappy groups.

The bottom-left and bottom-right are 5-shots each with .333 bushing and .3050 mandrel. Average velocity was 2944 (a full 45 ft/sec less) with SD of 7.46 ... and nice tight groups.

The "pull" on the ram for the larger bushing/mandrel combination was consistent, but very light resistance. The "pull" on the ram for the smaller bushing/mandrel combination was still smooth, but with slightly more pressure to seat the bullet.

The small surprise here was that a small change to increase neck tension provided much smaller group sizes at 100 yards.
The big surprise here was that slightly more neck tension actually reduced my velocity by a significant number, all other things being equal.

Any other surprises or observations from you "Neck Tension Mavens" out there.

 

[Lawnboi]

What was your actual neck tension between the two?

I used to load with light neck tension sometimes unknowingly. Seems like many of the top shooters prefer a little more tension, iv experimented a bit and found a little more neck tension to be beneficial.

 

[nn8734]

Do you measure your seating pressure for each round at all?

I'm wondering if it'd be worth buying and using a 'force gauge' or something similar...that combined with more testing can give you a 'range' of ideal seating pressures that you can empirically monitor / control for once you develop statistically significant/meaningful test samples by volume. Would enable you to quickly detect and identify any loaded rounds that fall out of that range and thus degrade the performance of a given prod lot.

Interesting preliminary results nonetheless.

 

[rustyinbend]

What was your actual neck tension between the two?

I used to load with light neck tension sometimes unknowingly. Seems like many of the top shooters prefer a little more tension, iv experimented a bit and found a little more neck tension to be beneficial.

That's a good question, but the only way to answer it (other than "feel") is by buying all the arbor press paraphernalia to accurately measure neck tension. I've spent so much on this hobby, that I've simply not invested there (yet). In this case, a little more neck tension certainly was beneficial. The next thing I think I'll do is to load with just a little more Retumbo, and see if I can get back that 45 ft/lbs while still keeping tight groups at this new neck tension level.

 

[rustyinbend]

Do you measure your seating pressure for each round at all?

I'm wondering if it'd be worth buying and using a 'force gauge' or something similar...that combined with more testing can give you a 'range' of ideal seating pressures that you can empirically monitor / control for once you develop statistically significant/meaningful test samples by volume. Would enable you to quickly detect and identify any loaded rounds that fall out of that range and thus degrade the performance of a given prod lot.

Interesting preliminary results nonetheless.

See my other answer to @Lawnboi ... "No" ... I haven't made that investment yet. I'm avoiding it for as long as possible. I've spent "enough".

 

[nn8734]

See my other answer to @Lawnboi ... "No" ... I haven't made that investment yet. I'm avoiding it for as long as possible. I've spent "enough".

Ya was typing didn’t see his post before I made mine…You seem to be an “in the weeds” type of reloader so think it would be a good investment when you have the funds.

Im prob going to buy one myself and use it for my 300 wm and 300 prc loads.

 

[rustyinbend]

Ya was typing didn’t see his post before I made mine…You seem to be an “in the weeds” type of reloader so think it would be a good investment when you have the funds.

Im prob going to buy one myself and use it for my 300 wm and 300 prc loads.

I've fought back the urge thus far ... but we shall see. If I can stay in single-digit SD's and hit a 1-mile target with my 300-WM, 300-PRC, 300-NM and 338-LM ... I think I'll be content (for a while). A "Seat-O-Meter" is really the only gadget I'm not using (yet) that I lust over when I see it.

 

[jafo96]

Interested to see if the groups still remain tighter once velocity is back up or if the group tighness is more from velocity change/harmonics than neck tension?

 

[MK20]

Hatcher mentions that the best lot of National Match ammo they ever made had some type of "cold weld" tendencies and took 600 ft lbs to pull the bullets if I remember correctly.

He said it shot fantastically. So with more tension it is quite reasonable to see an accuracy increase. I think it tends to smooth out any minor inconsistency in the powder by ensuring it all ignites uniformly before leaving the chamber.

 

[Lawnboi]

That's a good question, but the only way to answer it (other than "feel") is by buying all the arbor press paraphernalia to accurately measure neck tension. I've spent so much on this hobby, that I've simply not invested there (yet). In this case, a little more neck tension certainly was beneficial. The next thing I think I'll do is to load with just a little more Retumbo, and see if I can get back that 45 ft/lbs while still keeping tight groups at this new neck tension level.

Besides seating force did you measure the neck before seating and after to see how much it grew? Thinking interference not seating force.

I think it makes more sense for a field gun to have more tension, especially something that has rounds in a mag while firing.

 

[rustyinbend]

Hatcher mentions that the best lot of National Match ammo they ever made had some type of "cold weld" tendencies and took 600 ft lbs to pull the bullets if I remember correctly.

He said it shot fantastically. So with more tension it is quite reasonable to see an accuracy increase. I think it tends to smooth out any minor inconsistency in the powder by ensuring it all ignites uniformly before leaving the chamber.

The whole "more pressure for total ignition" thing makes perfect sense. That said ... I'm probably not ready to use a sledge-hammer to seat my bullets.

 

[Dave62677]

I’ve been testing neck tensions of my 338 for a while. Here is what I came up with. I went with the 0.004 bushing under then used the expander mandrel back to 0.002. Concentricity is always 0.0015 or under. The seating force consistently measured at 0.070 ~ 0.075in/lb with my arbor press.


338nm , 255gr badland icbm @2920 fps , ES 12

 

[rustyinbend]

Besides seating force did you measure the neck before seating and after to see how much it grew? Thinking interference not seating force.

I think it makes more sense for a field gun to have more tension, especially something that has rounds in a mag while firing.

You know ... I did the whole "neck-measure / bullet-measure / do the math / subtract the right number" ... thing, and that's what gave me the bushing and mandrel numbers that resulted in super loose neck tension that's not working well. I'm thinking experimentation is going to give me better results than the "standard way". These are competition rifles ... my wife won't let me hunt. And since she lets me spend ridiculous amounts of money on this hobby ... I don't argue.

 

[rustyinbend]

I’ve been testing neck tensions of my 338 for a while. Here is what I came up with. I went with the 0.004 bushing under then used the expander mandrel back to 0.002. Concentricity is always 0.0015 or under. The seating force consistently measured at 0.070 ~ 0.075in/lb with my arbor press.


338nm , 255gr badland icbm @2920 fps , ES 12

That's damn close to where I'm landing right now. Is your mandrel running smaller than caliber size? Mine is .3050 for a "book" measurement that says .3050 is the right number. BTW ... I'm liking the bushings from Short Action Customs. Crazy-expensive, but giving me amazing concentricity in the case neck.

 

[rustyinbend]

Interested to see if the groups still remain tighter once velocity is back up or if the group tighness is more from velocity change/harmonics than neck tension?

I'll report back via this thread after my next range visit ... probably early next week. Need to go into QuickLoad and do the math on what 45 ft/sec more equates to in Retumbo grains. Might even load a small ladder and see if I find a no-pressure flat-spot just above where I am. Things to ponder and test ... I'm glad I'm retired !!!

 

[Dave62677]

That's damn close to where I'm landing right now. Is your mandrel running smaller than caliber size? Mine is .3050 for a "book" measurement that says .3050 is the right number. BTW ... I'm liking the bushings from Short Action Customs. Crazy-expensive, but giving me amazing concentricity in the case neck.

I measure my brass neck thickness to determine size of the bushing. My equipments is not the top of the line stuff. My press is Lee classic cast, hornady bushing FL die, LE Wilson neck bushing, LE Wilson arbor seating die.

I tried 0.004 under and 0.003 under bushing then went through the same size expander mandrel, the bullet seating force is 0.020in/lb different. Well… reloading is just a game of trial and error. My group and ES does open up if my seating force is not consistent. I do anneal every firing with my blow torch.

 

[rustyinbend]

I measure my brass neck thickness to determine size of the bushing. My equipments is not the top of the line stuff. My press is Lee classic cast, hornady bushing FL die, LE Wilson neck bushing, LE Wilson arbor seating die.

Meant "book" mandrel size of .3060 where .3050 is what's working. Along with being a lousy shot ... I'm also a shitty typist. Are you measuring neck tension with the arbor die? My issue is I've got really good Redding Competition Micrometer Seating Dies for everything, so along with the cost of the arbor press and meter, I'd have to buy all new seating dies. I'm just not "there" yet when I'm getting single-digit SD's and hitting 1-mile targets. Maybe I'll get there someday ... but not "today".

 

[Dave62677]

You can say I’m measuring neck tension with my arbor press. If out of the blue one round seating force is way under or excessive , I do pull the bullet and dump the powder back to the jug and case prep the case again. You got to figure out which combination will work for you. I duplicated this methods and applied on my 6 dasher and it works great. 0.3 ~ 0.4 group with 15 under ES. I don’t really chase the single digit ES, anything within 15ES, I’m good. I keep my seating force above 0.050in/lb. The whole book number mandrel and bushing don’t work for me either.

For my 338 caliber, -002 neck tension is 0.070 seating force, my 6mm caliber -002 neck tension is 0.045 seating force. My 338 brass neck measured at 0.015, 6mm brass measured at 0.0135. So the neck thickness got something to do with the tension. I hope this help you guys

 

[jafo96]

There are 4 main aspect to seating pressure (assuming undamaged neck smd straight bullet alignment).
1) neck thickness
2) neck length
3) amount undersize
4) how much spring tension or wotk hardening the brass has.

Comparing different calibers one needs to also factor in change in surface contact area of a larger or smaller circumference ID neck/OD bullet

 

[M4orturnate]

In my small sample sizes i find it to be cartridge dependent. My 223ai like heavy tension, 6.5cm moderate, and 6br my groups tightened way up by decreasing tension. Ymmv

 

[bobke]

Maybe I missed it somewhere, but do you anneal brass, and with what method? Any chance that neck tension could be related to variable work hardening in necks that annealing could stabilize/mitigate? Have found the annealing process also brings consistent shoulder setback into the whole sizing result, which could possibly affect variance you may be seeing.

 

[rustyinbend]

Maybe I missed it somewhere, but do you anneal brass, and with what method? Any chance that neck tension could be related to variable work hardening in necks that annealing could stabilize/mitigate? Have found the annealing process also brings consistent shoulder setback into the whole sizing result, which could possibly affect variance you may be seeing.

I have an AMP ... and anneal after every firing.

 

[rustyinbend]

So this weekend, as I've been obsessing about neck tension ... a "SALE" Email showed up from LE Wilson with everything 10% off ... AND free shipping. I decided it must be a sign, so I've ordered the K&M Arbor Press with Force Pack, and SS Micrometer Seating Dies for all of my precision rifle reloading calibers (6.5-CM, 300-WM, 300-PRC, 300-NM and 338-LM). Soon I will no longer have to "feel" my neck tension.

 

[max1840]

So this weekend, as I've been obsessing about neck tension ... a "SALE" Email showed up from LE Wilson with everything 10% off ... AND free shipping. I decided it must be a sign, so I've ordered the K&M Arbor Press with Force Pack, and SS Micrometer Seating Dies for all of my precision rifle reloading calibers (6.5-CM, 300-WM, 300-PRC, 300-NM and 338-LM). Soon I will no longer have to "feel" my neck tension.

Congrats and keep us posted on your thoughts about the equipment and process after a few sessions

 

[rustyinbend]

Congrats and keep us posted on your thoughts about the equipment and process after a few sessions

Will do ... I "hate" sitting around waiting for shipping and delivery when I've got cool new toys ordered. What I'm "REALLY" interested in is to find out the actual pressure measurements around the "feel" where I've been adjusting bushing/mandrel combinations and saying to myself "that's too light", or "that's too heavy", or "that feels just right" ... on my single-stage press. I'm preparing myself to be surprised (again).

 

[MarkyMark007]

every week new thread from rustyinbend about his bushings and mandrells... and in every thread with different result...

poor boy, you realy think that reloding is so complicated that you have to try every combination of bushings and mandrells...

 

[MarkyMark007]

There are 4 main aspect to seating pressure (assuming undamaged neck smd straight bullet alignment).
1) neck thickness
2) neck length
3) amount undersize
4) how much spring tension or wotk hardening the brass has.

Comparing different calibers one needs to also factor in change in surface contact area of a larger or smaller circumference ID neck/OD bullet

on that list you MUST add:

-lube in the neck
-clean neck or carbon residue
-brass manufacturer (every manufacturer has different brass)

 

[rustyinbend]

every week new thread from rustyinbend about his bushings and mandrells... and in every thread with different result...

poor boy, you realy think that reloding is so complicated that you have to try every combination of bushings and mandrells...

It's all part of my personal journey, in search of the perfect long-range cartridge. Save your pity for someone that needs it. I'm having a great time with my retirement hobby. So much still to learn ...

 

[MarkyMark007]

in fact, it's a very good research what you are doing.

but it became a nonsense, in which you are searching for a perfect bushing and a perfect mandrell, in a 5-shot sample and with a brass, which became with every firing different than in previous firing.

so your results will be in contradict with previous with every firing with this approach. and that's a pity...

 

[rustyinbend]

in fact, it's a very good research what you are doing.

but it became a nonsense, in which you are searching for a perfect bushing and a perfect mandrell, in a 5-shot sample and with a brass, which became with every firing different than in previous firing.

so your results will be in contradict with previous with every firing with this approach. and that's a pity...

When I do comparisons, I try hard to keep all other things equal, as I'm using the same brand/firings of brass, annealer, cleaning, lube, sizing dies, seating depth, etc. In my current testing, the only thing I'm changing is neck tension, and doing that with bushings and mandrels. Most of my testing is with 10-to-15 shot cycles. If everything else is the same, and all I'm changing is neck tension, then I feel like the testing is valid ... at least it seems that way to me. If I can manipulate neck tension and see obvious changes in velocity and/or SD's ... that seems like it would be data that could reasonably be considered as accurate.

How and what would you suggest I do differently if testing/finding optimal neck tension is my objective? Any advice is appreciated.

 

[bobke]

MM007
Seems the journey is about reducing variables in the equation, but you have to identify same and take measures and capture data to confirm your findings-and then make the process as repeatable as possible. And be certain you can shoot the difference. So why bust a guy for going through HIS, not YOUR experience?

 

[Krob95]

I have not tested different neck tensions but one of the guys I know, he recommended 3k neck tension. He found it to be a lot more consistent and to all around shoot better which judging from your results above, may be on the right track. I'm thinking of going to a .2210 mandrel for my 22GT from a .2220 just to see if there is a difference at all.

Also it's peculiar that your speeds were slower with more tension. You would think pressure would build a little more resulting in the same or slightly more speed. Granted it's 0.5 thou which is next to nothing but still.

 

[rustyinbend]

I have not tested different neck tensions but one of the guys I know, he recommended 3k neck tension. He found it to be a lot more consistent and to all around shoot better which judging from your results above, may be on the right track. I'm thinking of going to a .2210 mandrel for my 22GT from a .2220 just to see if there is a difference at all.

Also it's peculiar that your speeds were slower with more tension. You would think pressure would build a little more resulting in the same or slightly more speed. Granted it's 0.5 thou which is next to nothing but still.

I know ... that seemed weird to me as well. As a result of that test, and believing the data I have accumulated thus far, I've built a 15-round "ladder" with the tighter neck tension charge weight, in .1gn increments, to take the velocity back up closer to 2900 ft/sec and see (a) if I can recover that lost velocity, and (b) where I experience pressure signs. Looking for the spot that (1) is below pressure signs, (2) shows a velocity flat-spot, and (3) gets me back that 45 ft/sec I lost with the higher neck tension. That range trip is scheduled for Friday. The data from that trip will (should) tell me the correct charge to load a 15-round group test. That's my plan. Having fun ... I love a good mystery.

 

[Dave62677]

Congrats bro. once you thought you figured out everything, then another mystery will puzzle the shit out of you. I Love reloading.

 

[rustyinbend]

Congrats bro. once you thought you figured out everything, then another mystery will puzzle the shit out of you. I Love reloading.

That's the way it's been so far in the 3 years I've been doing this. It's come in three phases:

• Phase 1 ... Why isn't this damn round chambering?
• Phase 2 ... Why can't I get consistent velocity and smaller groups?
• Phase 3 ... How do I get better SD's and tighter groups at long range?

Not sure what Phase 4 is going to look like ... but I'm sure it'll kick my ass, just like the other three phases have. I've had some interesting hobbies over the years, but this one is definitely the most challenging. It's really good exercise for my old brain.

 

[spife7980]

Not sure what Phase 4 is going to look like ... but I'm sure it'll kick my ass, just like the other three phases have. I've had some interesting hobbies over the years, but this one is definitely the most challenging. It's really good exercise for my old brain.

Phase 4 is the easiest. It finding a single process that you can do on any case with good results and stop chasing stuff.

 

[nick338]

Be interested to see if the group size was related specifically to the neck tension or if the extra grip on the bullet was keeping you in the velocity range the barrel likes. I see consistent neck tension as keeping the velocity consistent from shot to shot, all else being equal. I'm willing to bet bumping the charge to bring the velocity back up causes the groups to open up.

Looking forward to your range test.

 

[MarkyMark007]

How and what would you suggest I do differently if testing/finding optimal neck tension is my objective? Any advice is appreciated.

you are trying to find a 'global' best accuracy with different neck tension and same charge, but what if different neck tensions have different charges of powder and different OALs for their 'global' best accuracy?

in this scenario, which seems to be more realistic, you will need for any new tension develope a new charge and than you will see what is the best accuracy for your gun-bullet-powder-primer-barrel and neck tension combination.
but this is impossible to do because of too much testing.
and this test from your post #1 maybe indicates just this: you are out of tune for .335 bushing and .3055 mandrel. maybe a little different powder charge and you will have better groups than with .333 bushing and .3050 mandrel.
who knows!?

so in my opinion it's better in this new saga of 'mandrell is the best way of reloading' (after 'neck sizing is the best way of reloading' few years ago) to be focused on pure velocity variations SD/ES what in general works the best (not in particular, because 0.0005' differences are nonsense in my opinion, and if you try 4 different mandrells with 4 different bushings you will have 16 samples to test).
and that's why everybody is set on ~0.002' of neck tension, because you can't test every combination and the differences are not measurable between so similar dimensions.

and one comment from PRS blog:
The other scientific study on neck tension was done by Bryan Litz and published in Modern Advancements for Long Range Shooting Volume II. He tested 3 different cartridges (223, 243, and 308) with 0.001″ of neck tension (relatively light) and 0.003″ of neck tension (relatively heavy). Bryan shares the full details in his book, but I’ll just share his conclusion here: “The 223 Remington saw its SD improve from 9 fps to 6 fps for the higher neck tension. The .243 Winchester saw an even more dramatic improvement in MV, going from 13 fps to 7 fps! The .308 Winchester which already had a respectably low SD of 7 fps saw no improvement for the higher neck tension.” So basically, Bryan found heavier neck tension was better in most cases, and at the very worse it was as good as light neck tension.

and this seems to be better approach in this topic, much better than ''let's see if .3055 mandrell is better than .3050 mandrell for .333 bushing''

so maybe will be the best of you can prove what bushing (-0.001'/-0.002'/-0.003'/-0.004'...) and mandrell combination (-0.001'/-0.002'/-0.003'/-0.004'... from the bushing) works the best and give the best SD/ES; and in different calibers so this can be a new general rustyinbend rule, which all will follow...

 

[rustyinbend]

you are trying to find a 'global' best accuracy with different neck tension and same charge, but what if different neck tensions have different charges of powder and different OALs for their 'global' best accuracy?

in this scenario, which seems to be more realistic, you will need for any new tension develope a new charge and than you will see what is the best accuracy for your gun-bullet-powder-primer-barrel and neck tension combination.
but this is impossible to do because of too much testing.
and this test from your post #1 maybe indicates just this: you are out of tune for .335 bushing and .3055 mandrel. maybe a little different powder charge and you will have better groups than with .333 bushing and .3050 mandrel.
who knows!?

so in my opinion it's better in this new saga of 'mandrell is the best way of reloading' (after 'neck sizing is the best way of reloading' few years ago) to be focused on pure velocity variations SD/ES what in general works the best (not in particular, because 0.0005' differences are nonsense in my opinion, and if you try 4 different mandrells with 4 different bushings you will have 16 samples to test).
and that's why everybody is set on ~0.002' of neck tension, because you can't test every combination and the differences are not measurable between so similar dimensions.

and one comment from PRS blog:
The other scientific study on neck tension was done by Bryan Litz and published in Modern Advancements for Long Range Shooting Volume II. He tested 3 different cartridges (223, 243, and 308) with 0.001″ of neck tension (relatively light) and 0.003″ of neck tension (relatively heavy). Bryan shares the full details in his book, but I’ll just share his conclusion here: “The 223 Remington saw its SD improve from 9 fps to 6 fps for the higher neck tension. The .243 Winchester saw an even more dramatic improvement in MV, going from 13 fps to 7 fps! The .308 Winchester which already had a respectably low SD of 7 fps saw no improvement for the higher neck tension.” So basically, Bryan found heavier neck tension was better in most cases, and at the very worse it was as good as light neck tension.

and this seems to be better approach in this topic, much better than ''let's see if .3055 mandrell is better than .3050 mandrell for .333 bushing''

so maybe will be the best of you can prove what bushing (-0.001'/-0.002'/-0.003'/-0.004'...) and mandrell combination (-0.001'/-0.002'/-0.003'/-0.004'... from the bushing) works the best and give the best SD/ES; and in different calibers so this can be a new general rustyinbend rule, which all will follow...

A lot there I need to ponder ... thank you. As you noticed, I'm kind of coming at it from the other direction, by using a charge weight that I know is good for my rifle, and then tweaking the neck tension to get the very best SD/Group results. At that point I can raise the charge weight, and settle where I get optimized velocity, and no pressure signs. There are a few different ways to come at this ... that's the "RustyInBend Technique". If it fails miserably ... I'll try coming from the other direction.

 

[Yondering]

I’ve been testing neck tensions of my 338 for a while. Here is what I came up with. I went with the 0.004 bushing under then used the expander mandrel back to 0.002. Concentricity is always 0.0015 or under. The seating force consistently measured at 0.070 ~ 0.075in/lb with my arbor press.

I'm a bit confused about your force measurements - several times you've referred to "in/lb" of force, but that's not a measurement of force. Force would just be pounds (lb) with no inches involved. What are you actually measuring, specifically?

 

[Haney]

Convert inlb to lbin (Inch-pounds-force to Pound-inches)

How many Pound-inches make 1 Inch-pounds-force? Measurement calculator that can be used to convert inlb to lbin (Inch-pounds-force to Pound-inches), among others. (Torque)

www.convert-measurement-units.com

 

[Yondering]

Convert inlb to lbin (Inch-pounds-force to Pound-inches)

How many Pound-inches make 1 Inch-pounds-force? Measurement calculator that can be used to convert inlb to lbin (Inch-pounds-force to Pound-inches), among others. (Torque)

www.convert-measurement-units.com

Nope. That's about torque, not force. Does his arbor press measure torque instead of force?

 

[Haney]

Nope. That's about torque, not force. Does his arbor press measure torque instead of force?

Sorry, I don't have time to play the know it all game with you tonight .

I thought you learned your lesson when everyone slapped you around over your cast bullet bullshit ? Slow learner, eh ?

 

[Yondering]

Sorry, I don't have time to play the know it all game with you tonight .

More like "know nothing" on your part, Haney. Your comments are just one long string of not paying attention or commenting about things you know nothing about.

My original post was a legitimate question and didn't need your "input" and butt-hurt comments.

 

[rustyinbend]

The gauges that come with the arbor press measure "lbs of force" ... not torque measurements like "in/lbs".

 

[Yondering]

The gauges that come with the arbor press measure "lbs of force" ... not torque measurements like "in/lbs".

That's what I figured, but I've never used one, and wasn't sure what Dave62677 was referring to or how he was obtaining his measurement.

Besides, if it were a torque measurement it'd be in-lb rather than in/lb as Dave used.

 

[Cascade Hemi]

Rusty, when are you going to switch to F-Open and get serious about reloading?

Inch pounds are just 1/12th of a pound and can be an expression of force and mass. inlbf, inlbm, lbf, lbm. F=ma

 

[MarkyMark007]

That's what I figured, but I've never used one, and wasn't sure what Dave62677 was referring to or how he was obtaining his measurement.

Besides, if it were a torque measurement it'd be in-lb rather than in/lb as Dave used.

i think those indicators measure distance of spring contraction.

 

[rustyinbend]

Rusty, when are you going to switch to F-Open and get serious about reloading?

Good question ... I shoot in some local matches usually once a month or so. I prefer bench-shooting so F-Class would probably be fun. Some would look at my reloading room and bank account, and say I'm already "serious".

 

[Yondering]

Inch pounds are just 1/12th of a pound and can be an expression of force and mass. inlbf, inlbm, lbf, lbm. F=ma

Say what now? Lol.

In-lb would be 1/12 of a ft-lb, not 1/12 of a lb. Neither one are measuring force, that’s a torque measurement.

Besides, the guy I replied to used in/lb, totally different than in-lb or lb force. Those units all mean different things and can’t just be converted to each other.