Sorting 22LR for accuracy

[Brett33]

What a interesting read, I must have missed this thread first time around.

I used to sort ammo and shoot it, I have a science and stats backgound so I thought I would check if I was wasting my time.
I sorted batched sk match ammo on rim thickness and weight.
I ran a double blind type test on 3 groups of ammo,
Group 1 was top of the weight range with consistant rim thickness
Group 2 was the bottom of the weight range with consistant rim thickness
Group 3 was a random mix of the full weight range and rim thickness.
Got the wife to number the boxes and keep a record of which was which and went testing at home Night time with very expensive BR rifle and a mid range Chonograph, no idea which box had what ammo.
I shot on an RBA card with lots of aiming points and can get 7, 5 shot groups in a row, while recording velocity through the conograph.
While not a big enough sample size for true stats analysis the results surprised me.
Result 1: Groups between batches were not different on average. Good group hear, bad group there etc.
Result 2: Velocity between batches on average were not different, most importantly the really bad flyer you get 1 or 2 per box that drops low by about 10mm occoured in all 3 Batchs and had a velocity between 40-50fps slower.

The conclusion I have come to is the biggest problem is with the priming compound. It makes less then 5% of the charge weight and from limited research makes up over 50% of the Charge energy.

I now shoot expansive ammo, my rifle, like Bec's prefers Lapua Xact, really not surprised that like like the same ammo, we both use simular barrels, cut with the same reamer, buy the same fitter and turner.

The only problem is cost, when somebody asks me at comps how can I aford it, my answer is simple
I do not mind what I eat, but my rifle does!
If I have to trade beer and steak for water and 2min noodles to afford enough ammo for major comps so be it. No point driveing over 2000km return, to go to nationals and not turn up with ammo good enough to compete.

Brett

[SnipeWench]

I sorted my Lapua eXact ammo before the TRA Nationals, and shot a 598. Barry Hilzinger came first with a 599, I came 5th.

Anyway, reading Brett's post, made me think about what I've been doing since the TRA Nats - I've not sorted any of the eXact, just shot it. A fortnight ago, I did 3 details of 20 shots + sighters against the NSWSARAI benchrest cards, and scored my first ever 600. I shot two details of eXact (the first for the club comp, the second for the Winter League comp), then swapped ammo to Lapua Midas+ for the 3rd detail, because it was "practice" time.

My first card, I shot a 200 w/ 19 centres.

My second card, I shot a 200 w/ 20 centres (a perfect score).

My third card, I shot a 200 w/ 15 centres.

All up, that's 600 w/ 54 centres!

It didn't even _look_ like throwing shots that day - there were no scrappy 10's at all (where the bullet hole needs a gauge to be deemed a 10).

I think the accuracy is _partly_ due to the ammo, mostly due to the cleanliness of the barrel (I hadn't scrubbed it before shooting that day), partly due to the setup of the bench equipment (the front rest and rear bag), partly due to the wind (there was none, it was as dead as a doornail, until part way through the third), and partly due to the skill of the shooter.

So I don't batch them.

As Brett said, there's no point driving all that way to suffer through crap ammo.

Curran, I'm still intensely interested in your experiments results though! I buy expensive ammo so I don't need to batch, I know you can't buy exxy ammo, so you have to batch to get the accuracy up!

Keep experimenting!

[Rinso]

When will you all learn that 22lr and accuracy dont go together ... at least not consistantly.
Brett is 100% correct in his summation the primer compound is and always has been the culprit in Flyer's.
You just have to look at how primers react in centrefire rifles to see that the first thing to burn makes all the difference .. ie 300 Winchester Magnum burning 75 grns of 2213SC as compared to the little bit of material in the primer yet can make a huge difference to accuracy. Put a Fed210M in my load above and the rifle will/has shot 1.2 inch groups at 500M change that to a 215M and the groups blow out markedly ie nothing under 3 inches.
Unfortunately you cant change the primers in a rimfire so people have devised all these methods of removing fliers ... do they work? probably to some degree even if it is only in the area of shooter confidence.
I have said it before and I will say it again ...
Buy a comfy chair and a house brick, every Saturday arvo sit in the chair having a nice time and about every 20-30 minutes smack yourself in the head with the brick ... or go shoot rimfires for accuracy ... the result is the same a nice afternoon with intermittent headaches.

[Brett33]

I think the accuracy is _partly_ due to the ammo, mostly due to the cleanliness of the barrel (I hadn't scrubbed it before shooting that day), partly due to the setup of the bench equipment (the front rest and rear bag), partly due to the wind (there was none, it was as dead as a doornail, until part way through the third), and partly due to the skill of the shooter.

Bec, the bit you forget to mention is you run a barrel tunner. Depending on how much you have played with it since you bought the rifle I would suggest the FWB is very much in Tune. It was when I sold it. Why does that make a differance? because the little variation in velocity in the more expansive ammo is taken care of by the tunner. The greater velocity spread of the cheaper ammo can not be tunned out.

Bec, any chance of you shooting RBA with a top class field at Malabar 26/06/10. The high x count on the TRA target tells me you will run towards the front of the field at RBA if you can move around the target OK. The TRA target really is too easy!

Brett

[SnipeWench]

Hiya Brett,

Yeah, I forgot about the tuner! I do have a habit of ignoring that bit of steel and lead out there on the end of the barrel!

I have had a bit of a play with it since buying the rifle off Les. I found that the eXact ammo needed a slightly closer tuner (ie wound in a few turns) than the Midas+.

I'll have to see whether I'm available for the RBA shoot - been pretty busy with TRA and AISL shooting comps. BTW, where's the RBA calendar these days? It's certainly not up on the NSWSARAI calendar (even though NSWSARAI has taken over RBA).

[Brett33]

NSWSARAI do not take over RBA till next year. So the place to find match info is still
http://www.oz-rba.com/
Will be a good shoot and good test of Skill.
Brett

[curan]

I have said it before and I will say it again ...
Buy a comfy chair and a house brick, every Saturday arvo sit in the chair having a nice time and about every 20-30 minutes smack yourself in the head with the brick ... or go shoot rimfires for accuracy ... the result is the same a nice afternoon with intermittent headaches.

AAAaaaah......it's been a while since we saw the full "house brick as a rimfire BR accessory" analogy!

Good on you Rinso!