Anybody using the PRX?
- Thread starter Pete Wass
- Start date
Hello Pete, Hope that you're enjoying the winter wherever you are, still cold here in ME. What is this PRX formula all about ?
Dick
Although I'm not a CF benchrest shooter it seems to me that most CF tuners don't add length when adjusted. So how can the PRX formula, which depends on total length of barrel plus tuner, work on CF bench rifles? If I'm wrong, I apologize for questioning you Pete.
Jerry
Pete Wass
Well-known member
Well, I 'm not sure but
both CF and RF rifles use the same method of delivering bullets so it might be that the same factors that allow one to tune a RF barrel could work with a CF rifle. Makes some sense to me anyway. I think either kind of rifle can be tuned in a number of ways so the PRX may work for CF rifles as well.
In short, the length of the tuning device is what is critical when using the PRX. It's about harmonics vs weight alone.
Pete
both CF and RF rifles use the same method of delivering bullets so it might be that the same factors that allow one to tune a RF barrel could work with a CF rifle. Makes some sense to me anyway. I think either kind of rifle can be tuned in a number of ways so the PRX may work for CF rifles as well.
In short, the length of the tuning device is what is critical when using the PRX. It's about harmonics vs weight alone.
Pete
mwezell
Mike Ezell
Acoustics travel at the speed of sound. The PRX is an acoustic tuning method and most match rf ammo is subsonic. Not that it CAN'T apply to centerfire, but the acoustic waves become so close together, that tuning a cf at roughly 3 times this speed isn't feasible...IMHO...and I've tried it. The other thing is that vibrations don't travel through steel like acoustics, but much, much faster.
I feel you can luck into a spot from time to time, but that the acoustic tune won't hold....to many variables in play. More research is being done along these lines by myself and others, including Tony Purdy, who is credited with the PRX tuning method.
Jerry H
Different Drummer
I know of 1 case in CF BR that PRX worked. While I certainly believe in using PRX, I doubt that it is actually acoustically tuned. The exiting gases driving a subsonic RF are in fact supersonic themselves but may drop to subsonic very quickly within the tuner . I suspect that the PRX formula is a lucky coincidence that works about 75% of the time. It may be more related to fluid dynamics than sound. If it were a sound related tune, then it would work 100%. I have a duplex tuner that proves weight position is still a considerable factor. It allows independent weight and length adjustment with respect to each other.
SGJennings
New member
Two things:
1. There are two kinds of CF tuners. Those that extend beyond the muzzle and those that do not. The beyond-the-muzzle CF tuners can be viewed as increasing length. Mike's CF is a beyond-the-muzzle tuner.
2. Thank you, Jerry, for your observations about weight and length independence. That's good data.
Best regards,
Greg J.
1. There are two kinds of CF tuners. Those that extend beyond the muzzle and those that do not. The beyond-the-muzzle CF tuners can be viewed as increasing length. Mike's CF is a beyond-the-muzzle tuner.
2. Thank you, Jerry, for your observations about weight and length independence. That's good data.
Best regards,
Greg J.
M
mks
Guest
Jerry,
I think you hit the nail on the head. The fact that it sometimes works for CF means that the underlying theory is unsound.
CF bullets travel faster than acoustic waves, so acoustics has nothing to do with tuning.
mwezell
Mike Ezell
Jerry,
I think you hit the nail on the head. The fact that it sometimes works for CF means that the underlying theory is unsound.
Just a 75% coincidence rate I suppose, with rimfires. My tuners use the PRX but are not solely dependent on it. They still tune just like any other tuner that I've seen. The rimfire tuner uses a fixed length tube that is set to the PRX for that individual barrel, and the tuner moves behind it. The cf tuner extends beyond the muzzle and adjusts like a Lambert tuner, but the length changes when turned. I've already stated my view on the PRX and cf's. I won't go so far as to say that it won't work because of it's success with rimfires, but cf velocities present other issues with it being useful, so far.
M
mks
Guest
Mike,
I didn't mean to imply that your tuner or anyone else's don't work. The results are real. As you know, I have been using the Shade Tree for a couple of years now. My quibble is with the explanation of why they work.
Cheers,
Keith
I didn't mean to imply that your tuner or anyone else's don't work. The results are real. As you know, I have been using the Shade Tree for a couple of years now. My quibble is with the explanation of why they work.
Cheers,
Keith
Pete Wass
Well-known member
I have always found it interesting
that not much weight will tame a thick HV barrel; like 3 oz. and it seems to take 8 + with skinny little RF barrels - - - -, even at that, very little movement will affect tune big time. Wonder what 1 oz would do? I would prefer to have to move the tuner more to affect change.
Pete
that not much weight will tame a thick HV barrel; like 3 oz. and it seems to take 8 + with skinny little RF barrels - - - -, even at that, very little movement will affect tune big time. Wonder what 1 oz would do? I would prefer to have to move the tuner more to affect change.
Pete
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M
mks
Guest
I tried one on a 30BR that was pretty well tuned before the barrel went south. It made things worse.
mwezell
Mike Ezell
Agreed, but they become very close together that high.
I've spent quite a bit of time with them, enough to feel strongly that the barrel doesn't even 'see' or feel them before the bullet leaves unless they're 'way back from the muzzle, the movements are simply too small..
I also believe that many steel-on-steel tuners are erratic because they're tightened up in a way that allows 'rattle' or slop in the threads or rings. I believe that for a tuning system to be effective it must be very tightly fitted so as to provide immediate feedback. This can be a challenge when one leaves the butting shoulders small because turning down too far can bell the muzzle....... Some of the best are fitted with clamps.
al
P
pickles
Guest
Prx tuning
I just used it on my Shul, and it was very useful. I will use it on my other rifles an expect to have a great outcome.
Thanks Tony.
Pickles.
I just used it on my Shul, and it was very useful. I will use it on my other rifles an expect to have a great outcome.
Thanks Tony.
Pickles.