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AMP Annealer - Aztec Upgrade


Big Al

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3 hours ago, Big Al said:

Not quite, I just loaded the actual comp rounds rounds I needed which are 4x 5 shot groups. I will do another 15 later this week for foulers/sighters.

Quality rather than quantity for this game.;)

:)

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On 1/30/2018 at 11:57 AM, VarmLR said:

I can certainly buy into the engineering and science side of it Al, and to making everything as consistent as possible;  it just surprises me a little that no empirical evidence can be had.  For example, have you recorded more consistent and tighter SD/ES as surely that will be directly related to better neck tension consistency?

 

Bryan Litz and the Applied Ballistics LLC team are dong just that with a newly acquired AMP and written up in the Modern Advancements in Long Range Shooting series of collections of technical  and experimental essays.

For an engineer like yourself who wants to see empirical results, this has to be a must-buy set of material - not cheap but many of the range tests involve hundreds or even thousands of rounds fired.

Volume II (the most recent published) has started what Litz himself calls a look at lots of handloading 'givens' (eg high charge fill-ratio = improved consistency) and takes a very quick look at annealing effects on MVs and MV spread ES values as part of an in depth look at the effects of changing neck tension.

The author says that the AMP machine has to be counted an advancement in itself given its improvements in consistency, but by the time Volume II went to print, there was only time to do a couple of tests, one of which was cocked up so unfortunately doesn't tell us whether annealing gave any improvements. (He does say, its use will be investigated in depth in a future volume of the series.)

The two tests done were with 223 Rem and 308 Win, both Lapua brass and with load combinations known to work well and usually give good SDs. Three batches of cases were loaded and fired repeatedly 10 times and average MVs and SDs recorded. One batch of 10 cases wasn't annealed at all; one only once half way through the series of 10 firings; one annealed before each reloading / firing.

 Unfortunately, the wrong setting was put into the AMP for the 308 brass so the annealed results have been withheld. The 10 firings without any annealing showed no deterioration of SDs over the 10 firings.

The 223 with three levels of anneal (nil / once every 5 / every time) produced very inconclusive results. Although the annealed every time batch 'won', it did so absolutely marginally.

I consider 223 a poor choice for this test as such a low capacity case has MVs and spreads seriously affected by relatively small charge weight variations (0.1gn = ~10 fps) and charges were loaded as dispensed from an RCBS Charge Master which I know well struggles to stay consistently within a single tenth of a grain - it is only specified as + or - 0.1gn by RCBS after all.

Not a great result though for annealing and I hope / expect there will be a lot more as promised in a follow-up volume. In fact neither the rest of the neck-tension chapter, nor the other 'mythbuster chapters'  are exactly ringing endorsements of fancy / expensive kit. As I said these books are expensive, but they might actually save people a lot of money in some cases - eg a cheap flash-hole reamer / debur tool gives a fantastic return in terms of reduced ES values (but not on Lapua brass); but an £1,100 AMP (so far) doesn't.

I've always been one of the 'annealing extends the life of expensive brass' brigade, not the 'improves results in matches if done every time' crew. So far, I've yet to see anything that proves or disproves the validity of either camp's beliefs. :unsure: :unsure:

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The problem is - even with the repeatability of the AMP the 'on target' results rely on identical brass cases being annealed identically.

In other words, if one of your cases has a bit more weight in the shoulder (i.e thicker) then it may not perform identically (on target) when annealed with other cases in the batch.

I understand the Aztec upgrade can detect this.........

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3 minutes ago, The Gun Pimp said:

The problem is - even with the repeatability of the AMP the 'on target' results rely on identical brass cases being annealed identically.

In other words, if one of your cases has a bit more weight in the shoulder (i.e thicker) then it may not perform identically (on target) when annealed with other cases in the batch.

I understand the Aztec upgrade can detect this.........

The Aztec mode can be used to sort your brass by mass Vince. It is incredibly sensitive, and whilst demonstrating the guys at AMP moved the pilot a fraction of a turn and it completely changed the reading on the display in relation to the reference case. 

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Fascinating stuff, and thanks Laurie for taking time to share such a comprehensive response.  So really, what we so far have is that annealing prolongs brass life but may not affect SD/ES as much as we think?  At least over a few firings anyway. I guess that we need to undertake our own tests if it matters to us.  I do anneal, usually every firing but am wondering if I am wasting gas, as looking through past records for my ES/SD, they are remarkably consistent up to about 2 to 3 firings in between annealing.

I agree whole heartedly that with smaller case volumes, case consistency and charge weight accuracy are of equal/greater importance not to mention primer consistency.  The AMP is an impressive machine but so far, all I have heard is the wonders of the detail in terms of references/benchmarks/engineering detail and nothing of results on paper.  That's not meant to be an unfair statement, it just is what it is. 

Volume II of the Advancements in Long Range Shooting does sound like a "must have", so a call to March Scopes may well be in order :)

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