Yes, a lot of time went into it, and it only got started because I was recovering from illness. Very difficult to commit such time to these things when I'm healthy
To me, Benchrest is more a science project than enjoyable shooting
As I'm not interested in competition, I have no interest in competition rifles designed to excel on paper, I just enjoy actually shooting, whether hunting, plinking, or simply experimenting.
I resolved to find out for myself precisely which ammunition performed consistently the best for me in my rifles. I spent many, many hours researching all the types of ammo available in Australia, then I had my dealer get me everything he was able to. I also ordered a bunch of stuff online and made a trip up to Dandenong to collect it. The rest I ordered online and had delivered, several times as stock became available. I ended up with 100 different types of ammo, there are a handful of types I still have not been able to get my hands on. I still keep stock of those 100 types for testing in other rifles.Some of it was bulk ammo, a lot of it I ordered bricks to make life easier for my dealer. From memory it was a total in excess of 40,000rds, and cost me something north of $7000. Some of the exotic stuff was 70-cents per round (plus freight), the cheapest stuff I paid 7-cents apiece at $34/500rds on special.
Having tested most of this ammo in several rifles now, I've found that very few types behave badly, or differently, being fired in a bore coated with another type's lube, and the few that do, come good within 10-20rds or so anyway. If I found ammo that only performed well in a clean bore, it'd be useless to me, particularly when there are so many other types that allow me to enjoy shooting for 800-1500rds before accuracy starts to degrade and cleaning is required.
I also haven't seen a direct correlation between ES and accuracy (rimfire or centrefire), a few types give me SD in single digits, like CCI Standard Velocity, Tenex and Eley Edge, but other stuff with ES of 60 or more can shoot equally well, or better, like SK High Velocity (ES is a 5% velocity difference - with groups half the size of Tenex), or SK Rifle Match.
As far as I'm concerned, the only indicator of consistent accuracy comes from lobbing bullets at paper and measuring the result, not the velocity.
Wyliecoyote wrote:A lot of work there bladeracer. The benefit of competing in rimfire benchrest in the heyday of BR and Hunterclass is that one quickly learns what works in rimfires. Generally a quality barrel, match chamber where the rifling engages the bullet a grease ring or more, an action with a repeatable firing strike and finally the mystery batch of ammo. Anyone who has tinkered in this area can tell you rim thickness gauges are good at finding poor ammunition and are possibly unmasking the real issue of erratic ignition. But if used should be made from a portion of the barrel offcut and made with the same reamer the chamber was cut with. Weighing cartridges is an exercise in futility simply because you never know what discrepancies you are actually weighing. Light charge heavy bullet, heavy charge light bullet, primer mix or the case itself.
With rim thickness and factory head space, this is set around 44 thou to cover every possible breed of ammo. Some like Brno and 541s are around 42 thou.
Eley Tenex rims once measured about 41 thou when placed into a freshly cut chamber and measured with a depth gauge. So the head space on match rifles would be set at zero or more generally a half a thou crush on that 41 thou. But should you try to use something like Federal or SK or even some Lapua, the bolt may not close. Too bad if you got a poor performing batch of Tenex which was the case in the 90s. So yes this is all pretty unrealistic for a plinking rig but when you combine the 44 thou and then some, a rather generous chamber ID and feed chamfer cut, the bullet seated a mile off the lands, the chances of getting a shooter diminishes and feeding such rifles ammo like Tenex is like feeding strawberries to pigs..
Herein lies the problem with buying over the counter. PWS rifles for example are very hit and miss for accuracy. The bolt rim recess is around 44 thou. Some are deeper. Some settle for what they get, sell it off or choose to have it remedied because it doesn't shoot like the one on youtube. You can set the tenon length with infinite combinations of the factory offered barrel shims and still do no better than a loose 44 thou at absolute best. All you achieve is a smashed toggle bearing when an unknowing gunsmith tries to close the headspace too much and gets that toggle to snap shut. They are not meant to be forced, but operated by a solitary finger. Hence some of them never shoot to their potential or advertised hype. The bolt face, as Volquartsen now does (same action), must be machined to shallow the recess and get the front face off the back of the tenon, another major killer of accuracy.
Many factory rifles are set up on this loose standard, but a few like T1x, Quad and P94s, Anschutz BR50 etc are able to set headspace for any brand of ammunition by a barrel clamp arrangement. All have excellent ignition, a major factor in good rimfire accuracy, and all have barrels approaching custom grade.
With testing ammunition. Every brand uses different lubricants from grease, wax and mica and combinations of each. At no time is it advisable to shoot different lube based ammunition without cleaning between when looking for accuracy. You will get erratic results like a spectacular group that will never repeat, to shot patterns and everything in between. If you don't clean the bore, especially the throat, free of another brands lubricant and that dreadful crushed glass used in the primer mix, you are literally pissing in the wind. Yep it may take 5, 10 or even 20 rounds to prime the bore, but the test result will be real. The wives tale of never cleaning a rimfire is very quickly dispelled when one goes to any major benchrest match. Some barrels need long intervals, some shorter. But they are all cleaned.
What i always suggest to those who ask is buy to the objective you are happy with with both rifle and ammo. Clean the barrel and shoot the entire 50, foulers and all into groups of 5, 10 or whatever. By then you will see a pattern of groups from one barrel state to the other. If possible do it over a chrono to see if it correlates to velocity spread equals erratic groups. Note that 20 fps variance is worth 0.25" of vertical dispersion at 50 meters on ammo rated at around 1070 fps. Ammo with this capability or better is usually limited to the top end of the spectrum like Tenex, Black Match, Lapua X-act etc.