Reply With QuoteI've shot several breaks and most jump one way or the other and that is the reason I only use the JP break now.
didnt notice till I was shooting long distance at very small target. during recoil it jumps to the left every time. Just looking at the brake it looks balanced and timed right. I was trying to make sure I wasnt loading the rifle so it was getting pushed in that direction. Im sure I have a pic of it somewhere. My question is this. Can it be fixed; like enlarging a vent or port? I also was shooting off wooden table when I noticed it. Im going to do some more shooting of the ground but I still think some thing needs to be done.
1. so can it be fixed
or
2. scrap and start over
doc
I've shot several breaks and most jump one way or the other and that is the reason I only use the JP break now.
Unless the ports on one side are visibly larger than the other, there really shouldn't be that much difference. As LR said, most brakes will jump one way or another to begin with, and it's really up to the shooter to manager recoil and re-engagement. Shooting off a wooden table with a slide grade probably doesn't help tremendously either.
[I]"In the end, run what 'ya brung because it's better than nothing and don't give two ****s what some interwebs chat board guy says about your rig."[/I]
It will always jump to the left...it's called "torque". It's worse on faster twist barrels and lighter guns. A muzzle brake may tame rearward recoil, but it does nothing for torque. The only way to eliminate it is with a wider stock and heavier gun.
"As long as there's lead in the air....there's still hope.."
Performed this modification on 300 win mag when rifle was jumping to right.
BIASING
As produced, jp Compensators are "neutral"in lateral thrust, meaning they have no natural
bias to the left or right when firing. However, with just av ariable-speed hand drill,the
compensator can be easily modified to give a thrust bias into the support hand, which
makes the overall impulse of the rifle more linear for off-hand, kneeling or any position
shooting other than prone off bipod or weak-hand, in which case the modification will
actually work against the shooter.
Our original technique for biasing the lP Compensator was to drill a new hole through the
side of the comp on the flat area just behind the first expansion chamber. Since then,
we've found that it is just as effective, if not more so, to simply open up the two holes on
top of the comp as needed: the right ones for a right-handed shooter and the left ones for
a left-handed shooter.
Conveniently, this modification can be performed without removing the compensator from
the barrel. Simply lock the barrel securely in a padded vise so that you can easily access
the comp. The top holes of all jp Compensator models are 1/8"as manufactured, so begin
by opening the holes up with a 5/32"drill bit. Test the modification by firing a few rounds.
__ Then. incrementallv increase the_bore size, testing the rifle_after each increase until satisfied.
CAUTION: Muzzlebrakes by their very nature redirect high pressure gasses and can
blow dirt or other materials present in the shooting area back towards the shooters or
bystanders, especially at indoor ranges with enclosed shooting booths. Always wear eye
protection and ear protection when shooting or observing.
This device isconsidered a "compensator"by BATF, not a "flashsuppressor" and is not
designed or intended to be a flash suppressor.
THANKS FOR YOUR BUSINESS!
Visit us at www.jprifles.com
P.O. Box 378, HUGO, MN 55038- VOICE: 651-426-9196 • FAX: 651-426-2472
Can you give me more info about your set up. What biipod, stock/chassis, what brake, and weight of the rifle? It's possible some adjustments in shooting technique can help as well.
Have you read this article.
http://precisionrifleblog.com/2015/0...tay-on-target/
Neat chart half way through the article.
Its good to read also that others have had similar problem, i.e. jumping left. Initially when I noticed it I tried to take out or neutralize any body forces and just allow the rifle to act the way it would act and it still jumped left. Maybe the barrel would move an inch or so but that is big at 300 yrds. I am glad to hear that there may be things that can be done.
Its a Remington 260 with bartlien barrel mtu taper so its heavy. Cadex chassis and prs butstock and harris bipod. The brake is a custom from smith that trued the action, three large ports on sides that seem to line up quite well, three top vents and a vent at the 11 and 1 oclock position at the back of the brake.
I guess I didn't notice it off of front bags. I need to go back and test it under more conditions. I did go to prone off the ground and didn't seem to jump left however I was only shooting 100 yrds and it wasn't as noticeable. I only had 5 rounds left when I went to prone so Ill have to load back up and try some of the things I have read here and other places.
I think one of the things that made it more noticeable first of all is that was one of my goals yesterday was to try and keep sight picture so I was really concentrating on it. And secondly, my wifes new rifle has a different kind of brake and it stays straight although it will have to be replaced because it kicks dirt every where. (radial brake)
I like the idea of "tuning" the brake to compensate for torque. But I want to be absolutely sure its torque and not some stupid thing I am doing. I would hate to have the brake drilled on and come to find out my form is off. Cant go back till next Sat but I will have lots of time to dry fire. Ill look through some pics I have and post one of what it looks like.
Are you new to shooting with a Chassis? They do take some getting used too and are not as forgiving on recoil management as a more traditional stock.
This is my observation after running an XLR Element for the last year. You have to drive a Chassis like a Ferrari. Your form has to be perfect as it exaggerates any flaws or inconsistencies in your form.
The traditional high quality stock like a McMillan or Manners type seem to be more forgiving to me. Kind of like a good pickup truck. Fit is easy and comfortable and recoil is taken up much more naturally. I shoot better with a traditional stock as it has been more natural for me. In the end it's all personal preference, but I just want to point out the adjustment period with shooting a Chassis.
There are many theories on Muzzle Brakes and what works best. I think that's the most holes I have seen to date other than a radial though. I think a lot of it has to do with you adjusting to the new rig.
Last suggestion on my end would be when shooting off the bench using a bipod don't try to shoot it like a bench rest gun. Sit behind the rifle and not to the side. Pretty much like a prone position, but more upright. I like to pull the rifle into my shoulder slightly with my firing hand because it's quick and repeatable for any position I shoot from. When using a Harris Bipod I don't load it as it tends to "run away" or off to the side during recoil or bolt manipulation due to the way the feet rotate freely. An Atlas Bipod or similar type bipod on the other hand requires being loaded lightly for recoil management.
If your shooting with a bipod on a bench you will be apt to get muzzle jump.
Possibly something attached to the top permitting you to load the bipod would help.
Bipods are a wonderfull thing, but not necessarily for bench shooting.
Not new to chassis but new to a lighter weight chassis. The cadex is the lightest weighted rig in my safe. The barrel adds a bit more weight back but it does not compare to the savage 10 and 110's. Ive been shooting those for around 4 years. Its only been a few months that Ive had this rifle. Im just glad to hear its something I could be doing wrong. That means it can be fixed. Or at least minimized.
RPB.... So that adjustment Biasing was for rifle jumping to right? Im not going to change anything about the brake until I rule out shooter influence absolutely. But still good to know.
JP Industries doesn't define which direction. In my situation I concluded that by increasing the size of the right upper side ports would solve the issue.Originally Posted by doctnj
The torque doesn't have anything to do with the brake, it's the fact that the bullet is turning to the right and the barrel is turning to the left...action/reaction. This starts as soon as the bullet leaves the case. When the propellant gases hit the brake, the bullet is already out of the barrel. Biasing a brake will only redirect gas after the fact.
"As long as there's lead in the air....there's still hope.."
^^^This!!! I wouldn't drill or grind anymore on that brake. If you want to throw money at it, try a different brake and see if it works better for you. My preference remains the APA Gen II Little *******, but there are many good brakes out there. Try pulling the rifle back slightly into your should with your firing hand first. I good reference for how much is what ever the rifle ways try to put amount that much pressure. I.E. if your rifle ways 15lbs, pick up a 15lbs dumbbell and that's what the amount of force applied should feel like.
It didnt help matters that I was having a hard time putting good groups together as well. I sometimes dont understand how you can go out one time and shoot like a laser beam one day then on another, you cant put together one really good group. So then when I couldnt keep it on target my confidence went in the crapper. This will be eating my lunch all week till I can get back out and figure out what is going on. I appreciate all the pointers.
The first thing I have to do is get out and shoot off front bag and see if it still flips left. I realize that a bag will probably minimize the flip but if there is none at all or very very little then Ill realize that the rubber feet on the hard surface may have multiplied the issue. I need to shoot at distance with the bag as well as off the ground at distance then off bipod and compare all three. If they are all three similar results then I have to look very closely at me then finally the brake. That at least for now is my plan of attack.
My wife needs a new brake so we may look at the apa little b for her. That way I can see it up close and see how it works. Does it use a timing washer?
Last edited by doctnj; 04-05-2016 at 07:06 AM.
It's all fundamentals. Breathing, focusing on the crosshairs, trigger control, and building the same solid position every single shot when group shooting.
If you need to for practice actually write down your mental checklist and practice it every shot until it's muscle memory.
i have those days all the time and quit worrying about them...it still bothers me but i know that if i can go out one day a shoot a few small groups and the next day they open up i know its me not the load or the rifle...if your constantly second guessing everything you will always be chasing your tail...trust me i know!...and also why i stopped shooting groups and looking for a perfect load for almost a year and went into full test mode to see the effects of changes in powder charges,primers,case prep,weighing and sorting bullets,trimming meplats and a few other things...i found things that work well and other things that didnt work or didnt make a big enough difference for the added work.
with all that said i found the biggest thing is trigger time...after all that testing and playing with different things i started filming myself shooting and found several things that caused more problems than any of the loading or rifle issues i thought was causing problems...and at the top of the list was rolling my shoulder forward into the butt pad...that one took me a LONG time to correct and every now and then i still catch myself doing it.
as LW said work on fundamentals and dont worry so much about one hole groups they will come later when you have better control.
Well id agree with what LR said, but my question would be are chasis type guns shot off bipods intended to be
used for shooting small groups from benches? Would the same gun in a benchrest stock using a proper rest show different results?
Only because it's easier to shoot off a rest on a bench than it is a bipod because the rifle is mechanically driven rather than shooter driven...
Not sure I'm following you on that, but I'm assuming your saying the results depend upon the quality of the shooters.
To which I would concede, and ask that it always depends on the quality of the shooter dosent it?
I'm saying it's easier to shoot a BR set up off a bench (hence the reason it's called bench rest) due to the fact that you have a mechanical device to adjust and steady the rifle.
When using a traditional non-FClass type bipod it's up to the shooter to get into a good position that supports and steadies the rifle.
I'm not really impressed with accurate shooting with some of the crazy Bench gun or FClass setups that look like they take out every issue, but a wind call.
There was a guy that used to shoot our long range steel matches with a 35lbs 300WinMag F-Class Rifle using a mechanical front rest. He'd shoot the match clean almost every time with the furthest targets only being at 900yds. No one was impressed by it because any shooter on the line could win with that rifle/set up unless there was some really extreme wind or something. That's when the club starting running tactical matches more often and setup more rules about the set ups that could be used.
All I can say is that all you steel bangers could learn a lot by attending a real bench rest match and just observe. You may have the opinion that what bench resters do have no real connection to your discipline, and anybody could do it with that kind of equipment. Once you soak it in, you'll have a whole new way of thnking.
Every little accuracy improvement that is associated with precision shooting in the last 50 yrs., including bullets, barrels, bedding, powder, stocks, optics and other misc. gadgets and tools, can be attributed to a "bench rest shooter".
"As long as there's lead in the air....there's still hope.."
Posting Permissions
Bookmarks