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concentricity gauges etc


Swarovski1

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Run-out is important when attempting absolute accuracy but, most benchrest shooters will use the Wilson hand dies which produce adequately straight rounds.

 

For normal press dies, Forster take some beating.

 

A concentricity gauge of some form is a useful tool - if only to check that your dies are doing the job.

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Neil,pretty much as VInce says-concentricity guages measure concentricity,but they don't 'increase-or decrease it'. They just check what it is. Good dies-again as Vince -Forster or Wilson- and careful reloading are likely to get about as much practical accuracy under 'field' conditions as you would wish....improving wind judgement 5% would probably make a bigger contribution at anything beyond very short distance-something true for almost any level of intrinsic 'precision' in rig and ammo. (precision is the engineering component which the accurate shooter tries to exploit with human skill and good shooting solutions (ballistics etc).

 

g

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OK-Im no engineer!

How does the Lock'n'load know whether your chamber is concentric to the bore? Sounds like an altogether more serious condition,and unlikely,if your rifle shoots very well...

 

The (German) you tube video seems misleading in that it suggests a non concentric bullet somehow wobbles around as it passes down the bore-seems a bit extreme-given the bullet is the right fit for the barrel...I can see that entry off centre might dint the nose tip a bit-not too clever,to bash up your carefully re-engineeered meplets -But serious yawing in the barrel...all the way....experts can advise.

 

Basic remains,near zero concentricity is desireable and guages tell how close the ammo is to that-maybe some can reduce it too,in the guage?

 

Near zero runout woud also have a 'confidence' boost effect-helpful,but a feeling is not a "holes on paper effect"-though that may well occur.

 

Ultimately,only a proper test can establish whether there is measureable gains in any one rig,and the size of runout is but a clue to a 'maybe' improvement (especially assuming a reasonable base line run out already).

Perhaps someone can come in with expert advice on this,even actual before/after data on target?

 

g

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My rifles shoot really well, better that me, I guess runout concentricity must fairly good to shoot as they do, there is always room for improving my ammo though, am curious on the concentricity of my ammo now all the same, think I will just borrow a gauge to check before I attempt anything else.

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Neil,way to go.

 

A concentricity guage is $100-150.

 

You may well find your ammo is pretty good as is-and there is no guarantee that a slight reduction in runout would be noticeable in actual shooting....

g

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I would not use the Hornady tool which 'adjusts' concentricity after loading....surely it can only do so by bending the bullet in the case neck......cannot be a good thing I think?!

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I didn't mean actually bending the bullet itself but I think it uses leverage to realign it in the neck......I just can't believe it would be a good move....better to seek out the reasons for poor concentricity during the loading process itself.

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Here's a little story. About 15 years ago a guy called Vaughan Cherry got in touch with me. He had a device that would remove the run-out in loaded rounds and he wanted me to test it.

 

It was a nice bit of kit (if anyone is interested Brian Fox still has one) and he was under the impression that it had gone down big with the US benchrest shooters.

 

Well, I knew this was nonsense as I was in touch with a few of the US BR guys but I agreed to test it (I was writing for Target Sports mag at the time).

 

But how to test it? I eventually loaded up 20 6BR cartridges - using Wilson hand dies etc. - they were all pretty straight.

 

I decide to use Cherry's device in reverse - to bend half the rounds so that they had about 10thou.run-out.

 

I then shot the two batches at 300 yards using my 6BR benchgun.

 

Yup - you've guessed it - there was virtually no difference in group size! I must admit - even I was amazed!

 

Don't think that tool ever caught on!

 

Having said that - I do use a concentricity gauge - but only for 1000 yard BR.

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Thanks GP, thats answered my question and for many others too, you say you use concentricity gauge for 1000yds, I guess you load say 50 and measure and sort the rounds with the least runout, I only want to buy tools that actually serve a purpose rather than waste money on a gimic

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Hi GP, There I a thread on stalking directory you maybe intrested in, go on ammo and reloading, look for a thread does crimping affect bullet run out, a user called muir did an experiment for me by seating a bullet, turning case 180 degrees and pressing again to see if it halved runout, that myth buster got busted, he is a big fan of the case mouth expander, he measured runout on them and results were as good as or better than your wilson hand seater, maybe worth a try, it may give you an extra edge at 1000yds br .swaro

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I doubt if it bends the bullet, it must realine the case neck, it would be good to hear from someone who uses one and the results they got, probaly good on factory ammo thats bashed out 100,000's at a time.

 

I have one of these. I bought one about three years ago when I started reloading in my search for the 'perfect' round.

It works by exerting a sideways pressure on the bullet ogive using a screw in polythene ram. All well and good and it did reduce the runout, but it also marked or dented the bullet face surface. To me, it was swapping one evil for another.

The jury's out on whether it was very effective..not sure.

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Here's a little story. About 15 years ago a guy called Vaughan Cherry got in touch with me. He had a device that would remove the run-out in loaded rounds and he wanted me to test it.It was a nice bit of kit (if anyone is interested Brian Fox still has one) and he was under the impression that it had gone down big with the US benchrest shooters BR.

Vince,

 

Around about the same time maybe slightly later there was a similar sounding device called the Bersin Tool, which offered a two calibre option on each tool. I was suckered in and bought one and run some similar testing as yourself. Hence to this day it still sits gathering dust in the depths of the man cave, I even had Callum run an ackley reamer into it when I had a rebarrel done.

 

http://www.centuryarms.com/media/wysiwyg/pdf/BersinAmmunitionMeasuringAdjustmentDevice.pdf

 

I did a little search on "Vaughan Cherry" but couldn't find anything relevant, do you have a link? Just for an interesting read.

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Well it seems that these tools are about as much use as an ashtray on a motorbike.

I beg to differ. I have made a tool that gets my concentricity below a thou. I start with a very light neck tension so there is less strain on the neck whilst adjusting. When I have it adjusted below a thou I then run it through a factory crimp die. This last step does not affect the run off at - I've checked. This also halves my es and sd. I can run a loaded case through about every 5 seconds. Normally I only have to adjust about 1 in 5. My maximum runout beforehand can be up to 2-3 thou. I have found at 100 yards I have virtually no fliers. Best group to date is 0.160 at 100 yards for 5 shots. I only load for 223 so the machine is never adjusted. But it can be adjusted for other calibers. My adjustment screw is just above the neck as I don't like the idea of forcing the tip and straining the neck by doing so.

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The tool being discussed was the Swiss manufactured 'Bersin' device and was available in I think 12 models each covering a group or family of cartridges. It cost a fortune. The importer / distributor was Vaughn Cherry trading and registered as an RFD as 'VJC Supplies' of Banbury, Oxfordshire who lived in a really large and swish converted hilltop farmhouse or manor house on the Leics / Oxon border. VJC also imported the revived Danish Schultz & Larsen rifles and the top German EAW mounts amongst other things. VJC told me he was a retired MD for 'something large in the defence supply field' but it was too hush-hush to say what. In any event, he wasn't short of a bob or two, had a fullscale engineering workshop next to the house and was building a largeish gauge working steam model of some enormous American freight railway engine in it - a huge thing, around half built when I saw it. VJC Supplies is still listed by S&L as its UK distributor.

 

He asked me if I knew Vince (The Gun Pimp) and said he was an arrogant, ignorant man (or something like that). I told Vince at Diggle the following week that I'd met a friend and admirer of his, one V Cherry and got the response, an arrogant bloody fool (or something like that). Ha! Ha!

 

I actually tested the device on 6.5-284 handloads and factory 308 Win and found you could reduce the measured runout but it was almost impossible to eliminate it. I then did a test like TGP's with 45 rounds of 6.5-284 + foulers, one lot of 15 each as follows: straight out of the press; runout reduced to as low as poss on the device; runout increased to double figures on the device. Testing was 100 yard 5-round groups off the bench, a cartridge taken from each batch in rotation to avoid heating / fouling induced changes affecting relative group sizes. And yes ...........!! The largest 3-group average came from the near nil runout ammo, the best straight out of the die, and the super large runout batch was in between. Not big variations, but a definite trend.

 

I too have a concentricity gauge, in fact two of them, a Sinclair and a NECO (copy of a tool designed and made by the late great Creighton Audette) tool. I use them once in a blue moon. If ammo doesn't work as it should, it's worth checking bullet and/or case runouts otherwise it's just one more thing to worry about. Shortly after I got the Sinclair I loaded up 50 rounds of 303 for a P'14 service rifle with crappy Greek HXP brass, 174gn Sierra MKs, a North Devon Custom Firearm Services neck-sizer die and Lee bullet seater. Runouts ranged from near nil to 40 thou', probably had a modal value in the 15 to 20 thou' range. OMG thinks I, this is terrible. I'll have to demill the lot and start again. Then I thought, hang on, it's a near 100 year old P'14, the brass is fireformed to the likely non-concentric chamber, I've loaded lots of ammo the same way with the same components before and they've worked fine ... stop worrying!

 

So I did, and I had one of my best matches with that rifle the following weekend.

 

Incidentally, the American who is Mr. 21st Century Shooting Inc. (http://www.21stcenturyshooting.com/) once told me that the Sinclair (and Bersin) type gauge where the mic stem presses directly onto the case-neck or bullet will never give an accurate reading. You need a tappet or hinged finger system like NECO uses. http://www.neconos.com/item/Concentricity-Wall-Thickness-and-Runout-Gauge-12 He (the 21st C guy) used to make the Sinclair gauge under contract along with lots of other Sinclair branded stuff and knows a bit about this issue.

 

Double incidentally, I got poor runouts on the 6.5-284 ammo I was loading with 139gn Scenars for this test, too many at around 6 thou' and some nudging double figure values. Knowing a little more now than 15 years ago, I'd bet a reasonable sum that the bullet tip was bottoming out in the hollow seater stem before the bearing edge was in proper contact with the nose circumference. This condition kills concentricity and it affects most standard dies with all VLDs and most 6.5 and 7mm match bullets. I tried 7mm 162gn AMAX and 168gn Berger VLD in a large range of seater dies recently and ONLY Forster's supported bullets properly. The standard L E Wilson straight line seater drifts are also deficient with most 6.5 and 7mm match bullets and need either machining somewhat deeper, or the £20 'VLD drift' in the relevant calibre purchased.

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Thanks murph and laurie for replies though conflicting opinions, I am more curious than ever to check my runout, what is the part called needed to fit in the seater die so bullets not pressed in wirh the tip

http://www.brownells.co.uk/epages/UK.sf/en_GB/?ObjectID=12314&ViewAction=FacetedSearchProducts&SearchString=Wilson+vld+stem&ICShowAllFacets=1

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Murph,sounds OK-but just to be clear,are you saying your gizmo actually improves the precision of your ammo?

 

I mean,when you load normally,and have 2-3 hou runout thiose cartridges shoot measureably worse than when you use your gizmo torduce this 2-3 though to 1 thou.

If so,just what are two group measures,on average...likewise the improvements in ES and SD...a one off never repeated group no matter whether tiny or big tells nothing-only repeatable results can be informative.

And did you get flyers with 2-3 thou.....that really is pretty good anyhow,and would not normally give 'flyers'-ie shots that are clearly much more dispersed than normal.

 

NIce for you if you can confidently see consistent improvements that are measureable-but somewhat surprising that a reduction from 2-3 to 1 thou is as marked as you imply-though don't actually give measures for.

It's about helping others....with realistic expectations...most have been very luke warm on this when we are in the very low thou's anyhow.

 

gbal

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