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Reducing ES


colin jalland

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Colin,

Oh, bag of worms in asking this (after 'how do you clean your rifles and when?' 😉).

Think neck tension's got be up there in the mix? If you do some digging into history there was a bunch of BR shooters in the Texas that had an indoor range and did a slew of experiments/testing and it came out tops (from memory).

Case prep perhaps, annealing, primer 'fit' ??

T

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As pops says and annealing..

I had my best ES figures about 2 weeks ago trying 140gr hybrids in my 6.5x47 but only over 3 shots but I'm more than happy with that..

I've know others had a zero ES 🤩

I had the grouping to go with it 😁.

20201129_153649.jpg

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2 hours ago, colin jalland said:

Just a quick one ,after  consistent  powder weight what would you consider to be the biggest think to work on to reduce ES ?

Thanks Colin

Two articles (3rd waiting in the wings) all about this subject on PRB.

You probably know this but ES is only one metric to consider and probably isn’t the most important one either.

https://precisionrifleblog.com/2020/11/29/statistics-for-shooters/

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One small point is that you need an accurate and consistent way to measure velocity and  ES. The two top choices atm seem to be magneto speed and Labradar. I’ve used them together and got very consistent readings. The same can not be said for my  Chrony - light conditions alter the readings a lot.

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9 minutes ago, ds1 said:

One small point is that you need an accurate and consistent way to measure velocity and  ES. The two top choices atm seem to be magneto speed and Labradar. I’ve used them together and got very consistent readings. The same can not be said for my  Chrony - light conditions alter the readings a lot.

There is some suggestion that Labradar has about a 4fps SD tolerance for 30 cal rounds.  Not brilliant but I find mine useful.

 

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17 minutes ago, ds1 said:

One small point is that you need an accurate and consistent way to measure velocity and  ES. The two top choices atm seem to be magneto speed and Labradar. I’ve used them together and got very consistent readings. The same can not be said for my  Chrony - light conditions alter the readings a lot.

Yeah i use a Magneto sport which works very well

 

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10 minutes ago, colin jalland said:

Yeah i use a Magneto sport which works very well

 

may I ask how you know ?  I've read a measured test of Magnetospeed at  4fps SD tolerance 

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12 hours ago, No i deer said:

As pops says and annealing..

I had my best ES figures about 2 weeks ago trying 140gr hybrids in my 6.5x47 but only over 3 shots but I'm more than happy with that..

I've know others had a zero ES 🤩

I had the grouping to go with it 😁.

20201129_153649.jpg

ES from only three shots?? 😕~Andrew

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Incidently this load is exactly the same powder charge as my 140gr amax load with exactly the same base to ogive measurements and both shoot very small groups..

Seems like barrel timing is playing it's part in the equation and right on a node at 41.5grs in a 24 inch barrel.

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Reduce ES

Case prep

All cases - flash hole de burred, primer pocket cut to uniform depth, case length cut to exactly same length, chamfered inside and outside neck 

Weigh all cases 

Batch them 

Use only those of same weight or within a few grains of each other 

Anneal case necks

Tumble 

Seat primers exactly same depth

Weigh powder to lowest possible variance with your scales (mine are .02g resolution)

Wipe inside case neck with Sinclair wax (tiny amount) to provide consistent release assuming neck tension is correct with appropriate bushing 

Seat all bullets same depth (having measured shank length and sorted bullets to same length batches ) 

Repeat process above every time you reload 

Using the process above you should attain single digit ES - assuming your chronograph will accurately measure to that resolution 

Consistency is key to low ES  

 

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Single digit - low vertical dispersion at 1000 yd’s for example

1/4 MOA vertical dispersion would be, I suggest the baseline standard in zero wind conditions at that distance

 

 

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Mark, use a ballistic calculator and change your MV to match the variance  you are getting with ES and see how relevant it is at the distances you shoot. 

For example, 15fps may not be worth loosing sleep over at 200m or 300m but I know for me15fps at 1km makes a 14cm vertical spread before I start adding in other factors.

To meet Andy’s criteria of 1/4 moa I need single digit ES ( FPS) 

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33 minutes ago, Ronin said:

Reduce ES

Case prep

All cases - flash hole de burred, primer pocket cut to uniform depth, case length cut to exactly same length, chamfered inside and outside neck 

Weigh all cases 

Batch them 

Use only those of same weight or within a few grains of each other 

Anneal case necks

Tumble 

Seat primers exactly same depth

Weigh powder to lowest possible variance with your scales (mine are .02g resolution)

Wipe inside case neck with Sinclair wax (tiny amount) to provide consistent release assuming neck tension is correct with appropriate bushing 

Seat all bullets same depth (having measured shank length and sorted bullets to same length batches ) 

Repeat process above every time you reload 

Using the process above you should attain single digit ES - assuming your chronograph will accurately measure to that resolution 

Consistency is key to low ES  

 

\never been very happy with my primer tool and have been thinking of a replacement what would you recommend ? 

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Colin,

The combination of the C-21 adjustable pocket uniformer and adjustable primer seater is a good setup IMHO, not found similar products that work as well.

Pretty pointless seating the primer to the same depth if the pockets are all different!! 😉

T

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7 hours ago, Andrew said:

Reduced ES ? Uniform pull weight.~Andrew

I think Andrew raises an excellent point here.  We fuss around the reloads but do we give the same attention to the nut behind the trigger?  Perfect tools do not make a craftsman  (but of course they help).

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Little point in pocket uniforming unless primers are sorted for depth too.  I attach the SAAMI spec drawing.  You can see the allowable tolerances are large - 13thou on depth of primer cup for LRP.

Primer dimension chart copy.png

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10 hours ago, Ronin said:

Single digit - low vertical dispersion at 1000 yd’s for example

1/4 MOA vertical dispersion would be, I suggest the baseline standard in zero wind conditions at that distance

 

 

 

9 hours ago, ds1 said:

Mark, use a ballistic calculator and change your MV to match the variance  you are getting with ES and see how relevant it is at the distances you shoot. 

For example, 15fps may not be worth loosing sleep over at 200m or 300m but I know for me15fps at 1km makes a 14cm vertical spread before I start adding in other factors.

To meet Andy’s criteria of 1/4 moa I need single digit ES ( FPS) 

Thank you for the info it gives me a good starting point as I have a load that is now doing half inch at 100 metres if I pay attention, so it will be interesting to see what the es is once I can arrange to borrow the chap down the club's lab radar

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