Transitional ballistics

S

smoke

Guest
There have been long discussions on this forum re tuners, weights, weight in front of tuners/noodles, nodes, etc. Most of this is in the "transitional ballistics" arena, i.e. effects at or near the muzzle of a rifle. Since it seems that most of these discussions involve weight, mass and their relationships almost exclusively, I am wondering what testing has been done regarding the effects of the propellant gases at the muzzle. While a lot seems to have been done in this area involving large caliber (Tank / Artillery), as well as on CF rifles, there seems to be a lack of info concerning these effects on our rimfire rifles. Any informed info would be appreciated. Bob Vail
 
No he is not talking about muzzle brakes. He is talking about the gases that follow the bullet to the muzzle and what effect it has on the bullet when it leaves the barrel. A muzzle brake dampens the effect of recoil by allowing gases to vent out of the holes in the muzzle brake which causes less recoil felt by the shooter. Garrisone.
 
No, muzzle brakes, flashiders, recoil suppressors all have a specific purpose. My inquiry relates to rimfire accuracy and the possible effects of the escaping gases(and the control therof) on accuracy .
 
smoke, most 10 meter match air pistols have an air stripper on the end of the barrel. I've been told that it is to strip the turbulence caused by the air being pushed out of the barrel ahead of the pellet but I don't see why it wouldn't do the same to the air pushing the pellet as well.

It would be an interesting experiment to try one on a rimfire.
 
Mr Papas: according to your post are you saying your noodle is a type of muzzle brake ? garrisone.
 
Thanks to both wlb and James - think we are on the right track here. First, what does an air stripper look like? How is affixed to the bbl.? Next, (forgive me if I am wrong on this), we are dealing with 2 columns of "gas", the first is the air in the bbl. which is compressed as the bullet moves down the bbl., The second, is the expanding gas from the primer/powder combustion process. This latter gas,as it exits the muzzle, is actually moving faster than the bullet(for a few inches), as I understand it. Both these"columns" disipate to a degree as they encounter a larger column (inside the J&J slider for example),then are furthur vented to the outside via some variable slots. While I understand that this has led to some accuracy improvements,it would seem that we may have only scratched the surface on this subject -it would be interesting to see high speed photos of rimfire bullets,and the attendent gas dispersal pattern (like the pictures shown in some ads -enhanced of course). Again, what info on this subject is available and does it have relavance?
 
Does it have some relevance? yes, proven point in other arenas. Any deformity of the other variables will overshadow it though.
Other variables:
Projectile
Lands
Grooves
Crown
Vibration/ force wave/ or what ever you wish to call the deflection of the barrel as the projectile is driven through its length by what ever means.
If I remember correctly a lot of discussion on this subject was brought up during the heyday of Bloop tubes in silhouette, some also in the smallbore prone competitions in reference to a crosswind at the muzzle and in precision air rifle which is more specific to your question. In air the compensator/ stabilizer and various methods of stripping the pressure away prior to the projectile exiting the bore ( on c02/pcp units) was to negate muzzle flip and to a lesser degree possibly influence the projectile path due to the redirection of the propellant mass behind the projectile at the instant of projectile/barrel seperation. The current crop of Olympic air units are almost completely void of any muzzle flip, vibrations, or recoil ( .177 cal, 550-650 fps projectile velocity, 7.9-8.5 grain projectile weight).
 
if your rifles were bedded properly by someone like Alex sitman and tuned properly which most bench rifles are not escaping gas wouldn't ever be thought of. take care of tuning and timing first. and forget the do-dads.
 
Martin

martin hammond said:
if your rifles were bedded properly by someone like Alex sitman and tuned properly which most bench rifles are not escaping gas wouldn't ever be thought of. take care of tuning and timing first. and forget the do-dads.
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Hey Martin, 4 of the top 5 shooters on the ARA A-Line were using a parallel noodle, slider or bloop tube. The top shooter on the Agg line was using a noodle. That speaks louder than any bull$hit you put on BRC.
 
J Pappas said:
Hey Martin, 4 of the top 5 shooters on the ARA A-Line were using a parallel noodle, slider or bloop tube. The top shooter on the Agg line was using a noodle. That speaks louder than any bull$hit you put on BRC.
Click to expand...

Well said James.

Would an airgun type stripper improve accuracy on a rimfire? I don't know, but it would seem to be worth a little experimenting. By the design of the things, I have to think there is more to it than just reducing muzzle flip. They are easy enough to make if you have a lathe and a milling machine. I made one for a CO2 pistol I made for my wife. The muzzle brake aspect of it definitely reduced muzzle flip to a negligible amount. I don't know what it did for absolute accuracy because at this point it was a monkey see (on my Walther LP300), monkey do thing as I currently lack a machine rest to quantify such things.

smoke, I'll take some pictures of the one on my Walther and of the one I made and try to get them posted in the next few days. The Walther is attached with set screws and the one I made is a very light interference fit.
 
I forgot to add that the stabilizer in the air units is there to negate the force used to pop the valve open. It is a moving mass assembly. When they get out of sync horrible things happen to your shots. So perhaps this is an area that needs more attention, previously alluded to in other discussions on this board in regards to firing pin impact vibration ect.

Happy turkey day to all.

Best news i have had in awhile, my middle son is rotating out of Afghanistan, should be back state side around the the beginning of Dec. ( Sargent in Army Rangers Special Ops)
 
James, follow the money. more money is made from untuned rifles than anything else. just because things have been done incorrectly for 20 years is no reason to continue for another 20. look what Calfee has been doing and is doing so right now. a new barrel to make his improperly set tuner work. only in the world of bench shooting would people go thru all the rigging to reinvent the wheel. a good tracking stock, ignition, decent barrel a properly tuned rifle and a good bedding job is all that's needed, the rest is tinkering which it's obvious bench shooters love to do. oh and happy thanksgiving.
 
Thanks for the comments - am looking forward to wlb's pictures and , hopefully, some additional constructive information. Bob
 
smoke, I didn't know how to put pictures on this forum so I made a new album on my website: http://www.wlbsite.com/
Click on "Photos", scroll down to "Shooting Photos" and click on "Airguns"
the first photo is the one I made, the rest are the Walther.

According to the instruction manual for an Aereon air pistol, the position of the cone relative to the end of the barrel is supposed to affect the tune of the air pistol but until I make some sort of machine rest I won't be able to test that.
 
THANKS!! Nice pictures and nice site. The one you made in your shop really clarifies the device - good job! I take it that the cone has some back and forth adjustment and can be locked in place -setscrew? Much appreciate your information. Bob
 
An assumption

If the crown is "good" and the bullet is "good", the gasses will affect the bullet uniformly and become insignificant. An attempt to eliminate the need for a "good" crown would likely move the need for "good" to another area.
 
Wilbur, I don't think this muzzle brake/air stripper device was an attempt to eliminate the need for a good crown. I know it wasn't on my part. I consider the crown to be EXTREMELY important on anything that shoots.

My best guess--and that is all it is--is that a muzzle brake was necessary to remove all movement from the firing cycle and that the stripper directs the turbulence created by the brake away from the pellet. Pellets are relatively slow moving and spend more time in the brake area so the turbulence likely induced some inaccuracy.

Another guess would be that if such a device proved to be effective in rimfire benchrest it would be because of decreased gun movement making riding the bags the same each time less critical. I do not think such a device would eliminate the desirability of a tuner.

Bob, the cone is a press fit on the Walther. Apparently they thought they found the best distance from the muzzle and did not need to make it adjustable. From the test target sent with my pistol I would have to agree. 10 shots at 10 meters through what looks to be one single hole. No discernible dispersion. I made mine with a very light press fit and set it to the same dimension as the Walther. The Aereon that was adjustable did not have, and did not claim, one hole accuracy.

I'm an old dinosaur, my son made the website for me and is slowly teaching me how to post pictures but he does get tired of having to retrain me every month or so. :) :) :)
 
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wlb said:
I'm an old dinosaur, my son made the website for me and is slowly teaching me how to post pictures but he does get tired of having to retrain me every month or so. :) :) :)
Click to expand...

Your website is a prime candidate for one of those free content management systems. Google both Drupal and Joomla and talk your son into getting one of those running. Makes it real easy to add content without knowing how.
 
Wilbur, my son said Drupal and Joomla are options with the Coppermine album manager. He said he would set me up to try them after he has his finals. Thanks for the tip.
 
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