Tony
I have seen stretchers used in TR before, few and far between, one of the people using them was Don McDonald, he said that the rifle did shoot better but was expensive when paying someone else to do it. He now shoots F Class due to health reasons and just uses heavier barrels. This was 4-5 years ago when technically tuners weren't allowed and he had no problems.
Can the stretcher butt up against the action ??
How close a fit does the tube need to be on the barrel ??
Does the nut have a step on it to centralise the tube ??
What thread do you use and how tight does the nut need to be ??
If you can pass on some of your hard earnt knowledge I'll be the test pilot.
Matt P
Question for all F Standard shooters.
Matt thanks very much for that bit of info. No-one is suprised more than me that a stretcher has been used in TR. This puts a different light on things for me. We may be the two test pilots.
I will get some pictures of different styles of fitment and post them. The tube is important as it must be a T5 (the T stands for tensile strength) minimum and the material should be a 5000 grade atleast but the 6000 grades are preferable. The chamber end of you barrel i assume is 31.75mm in diameter or thereabouts. There is a tube suitable to butt over the barrel and onto the action face in this size. Its OD is 38.1mm and may need to be skimmed down to fit a narrow barrel channel otherwise the channel needs to be opened up. The material part no is E40015MF605600 and is a 6060 T5 grade. Wall thickness is 2 mm so the tube has just over a mil radial air space. There are thicker wall tubes available in this grade that can be skimmed down externally and bored internally to be a neat fit over the barrels chamber end if you are using a Palma profile and have limited barrel channel clearance. The second option is the best as when assembling the whole thing, heat sink grease can be used over the chamber end for a 100% heat transfer which helps greatly on the long shot strings. This is one of the other advantages the tube gives as aluminum is a very good heat sink and the chamber temperature dissipates very quickly. Needless to say the fit at the chamber should be held to a thou or even size for size and in order to do this, a very light skim of the barrels chamber end to get it true may be required but not always neccesary. The muzzle should not be brought down greatly in size to suit some thread size. The thread size should be determined by the muzzle diameter. ie, Palma profiles can vary a little but generally it will be possible to turn either a 20 x 1.5 metric or 0.75" UNF imperial thread on the muzzle without having to remove much material to bring it to the right size. Then a nut can be made up to suit, tube cut to length, all assembled, the rifle have say ten shots fired through it and the nut snugged up. This is very important as 416 grows more during heating than will the external alloy tube until the heat transfer gets going and often the tube and nut can loose tension. There must always be some sort of tension, even just a little or the shots get slung about and the tube will be heard to rattle. I have never had a problem with this.
The addition of "o" rings as seals and tubes being filled with water, coolants or oils etc, is a total waste of time. Just plain old air is the best. There are a lot of tube materials other than aluminium that could be used. Stainless steel tubing of the welded seam type is disasterous. Steam, seamless or Shedule stainless tubes also do not work. Titanium i have not tried, but can be purchased from bicycle manufacturers in certain sizes, but the fusion process used in manufacture would make me think it not suitable. But i don't know for sure. If i have forgotten anything i will post it with the pictures.
Tony Z.
I will get some pictures of different styles of fitment and post them. The tube is important as it must be a T5 (the T stands for tensile strength) minimum and the material should be a 5000 grade atleast but the 6000 grades are preferable. The chamber end of you barrel i assume is 31.75mm in diameter or thereabouts. There is a tube suitable to butt over the barrel and onto the action face in this size. Its OD is 38.1mm and may need to be skimmed down to fit a narrow barrel channel otherwise the channel needs to be opened up. The material part no is E40015MF605600 and is a 6060 T5 grade. Wall thickness is 2 mm so the tube has just over a mil radial air space. There are thicker wall tubes available in this grade that can be skimmed down externally and bored internally to be a neat fit over the barrels chamber end if you are using a Palma profile and have limited barrel channel clearance. The second option is the best as when assembling the whole thing, heat sink grease can be used over the chamber end for a 100% heat transfer which helps greatly on the long shot strings. This is one of the other advantages the tube gives as aluminum is a very good heat sink and the chamber temperature dissipates very quickly. Needless to say the fit at the chamber should be held to a thou or even size for size and in order to do this, a very light skim of the barrels chamber end to get it true may be required but not always neccesary. The muzzle should not be brought down greatly in size to suit some thread size. The thread size should be determined by the muzzle diameter. ie, Palma profiles can vary a little but generally it will be possible to turn either a 20 x 1.5 metric or 0.75" UNF imperial thread on the muzzle without having to remove much material to bring it to the right size. Then a nut can be made up to suit, tube cut to length, all assembled, the rifle have say ten shots fired through it and the nut snugged up. This is very important as 416 grows more during heating than will the external alloy tube until the heat transfer gets going and often the tube and nut can loose tension. There must always be some sort of tension, even just a little or the shots get slung about and the tube will be heard to rattle. I have never had a problem with this.
The addition of "o" rings as seals and tubes being filled with water, coolants or oils etc, is a total waste of time. Just plain old air is the best. There are a lot of tube materials other than aluminium that could be used. Stainless steel tubing of the welded seam type is disasterous. Steam, seamless or Shedule stainless tubes also do not work. Titanium i have not tried, but can be purchased from bicycle manufacturers in certain sizes, but the fusion process used in manufacture would make me think it not suitable. But i don't know for sure. If i have forgotten anything i will post it with the pictures.
Tony Z.
The pictures as promised are a little late. These are the action washer and threaded lock nut aswell as a closeup of a stepped shoulder where the washer is not required or not able to be used. The groups shown are of my first HG i built in the 90s and show the nut locked up on the tube. The tube is 32 mm OD and the barrel is an old FB barrel i got off me old pommy mate Mastin up on the Tablelands. Twist is 14. Even with this old barrel and the tube some good results are still possible with 165 CDCs. As you can see from the groups at 200 yds the groups don't vary a lot and most of the variation is more likely from a condition. The only real change is a very slight elevation shift as the velocity increases and the usual group shift and size variation is not evident from what a bare palma profile barrel would be expected to produce. So the tube does a good job of tuning out the normally seen barrel whip. As you can see from the groups, a cartidge could be loaded with a range of plus or minus 2 grains and still produce a respectable group, something that could never be done with a bare barrel. Of course such a variation of charges at longer ranges show up as vertical slots. You can now clearly see why it is posible to choose your speed or brass yeild point without compromising group potential and how JR tightens her up until the thing strips and then backs it off half a turn or rather half a grain, and then goes out and shoots. Incedently, this barrel is used for fireforming cases for our 30 Redneck and all the bullets shot are not AAA.
Tony Z.
[/img]Matt i hear you put some red faces on some FO shooters with the new gun over the weekend. Not bad for an old worn out FB barrel.
Is that a Quadlite action? Best of luck at the NSW Queens, i'll be at the Hunter Nats that weekend. Total sellout at Springsure for the Custom RF with 60 shooters for the Sunday match. This will be the biggest turnout for a Hunter event for years. Still gunna miss Barry Duncan not being there.
Tony Z.
Is that a Quadlite action? Best of luck at the NSW Queens, i'll be at the Hunter Nats that weekend. Total sellout at Springsure for the Custom RF with 60 shooters for the Sunday match. This will be the biggest turnout for a Hunter event for years. Still gunna miss Barry Duncan not being there.
Tony Z.
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Matt P
- New Member
- Posts: 91
- Joined: Mon Jan 08, 2007 7:17 pm
- Favourite Cartridge: 6BR
- Location: Castle Hill NSW
Rinso
Shot it for the first time on Sat @ 500M, the elelvation for both loads was around the 1.5" mark, well under the 10 ring on the open target.
The stock is by Phil Mastin to my specs, the fit and finish is outstanding would recommend his work to anyone looking for a new stock.
Tony
No it's not a Quadlite it's a RPA2000, it was the model before the Quadlock, it has the same bolt a Quadlock but uses a round action.
The point of impact moved quite a bit once the tube was fitted but I guess that is expected as most barrel aren't dead straight.
Matt P
Shot it for the first time on Sat @ 500M, the elelvation for both loads was around the 1.5" mark, well under the 10 ring on the open target.
The stock is by Phil Mastin to my specs, the fit and finish is outstanding would recommend his work to anyone looking for a new stock.
Tony
No it's not a Quadlite it's a RPA2000, it was the model before the Quadlock, it has the same bolt a Quadlock but uses a round action.
The point of impact moved quite a bit once the tube was fitted but I guess that is expected as most barrel aren't dead straight.
Matt P
-
Matt P
- New Member
- Posts: 91
- Joined: Mon Jan 08, 2007 7:17 pm
- Favourite Cartridge: 6BR
- Location: Castle Hill NSW
Rinso
To be honest, with 155's and target used if it continues to shoot like it does, load developments over. The smallest scoring ring at every distance is 1MOA or bigger so all I need to do is learn what the 155 does in the wind and continue to learn how read conditions (never ending battle, the more I learn the LESS I know).
Matt P
To be honest, with 155's and target used if it continues to shoot like it does, load developments over. The smallest scoring ring at every distance is 1MOA or bigger so all I need to do is learn what the 155 does in the wind and continue to learn how read conditions (never ending battle, the more I learn the LESS I know).
Matt P
Matt,
I was just about to say the same thing.
One thing you may be able to do with the stretcher is push them out as fast as they'll go and still retain the accuracy, i.e no need to tune in the conventional manner. I think that was Jeff Roger's theory. If you can have them that accurate (about 0.25 MOA) and a velocity of over 3000fps, it will be a mean machine for FS!
Alan
I was just about to say the same thing.
One thing you may be able to do with the stretcher is push them out as fast as they'll go and still retain the accuracy, i.e no need to tune in the conventional manner. I think that was Jeff Roger's theory. If you can have them that accurate (about 0.25 MOA) and a velocity of over 3000fps, it will be a mean machine for FS!
Alan
Jeff, you are correct. It was Tony's "idea", in one of the earlier posts on this thread :a.JR wrote:Al , You got it wrong about me again...
AlanTony Z wrote:At no time has a tube fitted to a barrel given smaller groups than the same barrel without the tube. The difference is that the velocity can be chosen, definetly at the top end for those shooting LR, within the guidelines of the cartridges safety limits and the group does not suffer greatly.