Barrel Whip

[Danehunter]

->I stiffened the forearm of my (former) 6.5 CM Ruger American Predator plastic stock by Dremeling out a groove for a heavy aluminum arrow to lay in.
->Next I built putty "dams" near where I would put epoxy to keep it in place and from running down into the bottom of the forearm.
->Finally I mixed up some JB Weld and epoxied the arrow shaft in place the full length of the forearm.

After it hardened I removed the putty dams and that forearm could NOT be bent against the barrel by pulling on my sling.

Eric B.
P.S. But now I have a Browning X-Bolt Pro and that carbon fiber wrapped stock's forearm is rigid! But at that price it should be!

 

[Overkill338]

....you know you got to whip it....
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Whip it gooooood!

 

[OrionsStar]

Pressure bedding works well for certain sporter barrels. I was taught when the forend needs stiffening to bed in push rods witch has worked well for me. If you are going that route of a plastic / rubber stock make sure you dremel groves for the bedding to hold onto.

 

[epoletna]

My experience in building aircraft with composite materials tells me that the strength is not in the resin, it is in the resin-impregnated carbon fiber. If you can get some carbon fiber strands, soak them in resin, then lay them into the space below the barrel channel, you should be able to stiffen the stock appreciably. But just pouring resin into that space will not be as useful.

 

[Frank in the Laurels]

A few moons ago there was a 6.5/284 light gun that had a visible whip that was actually fun to watch...never saw one worse in 5 decades of benchresting

 

[cohunt]

Of you are going to insert something in the forearm to stiffen it-- use a carbonfiber arrow shaft epoxied in place

 

[AZShooter]

Enjoyed the video even though I was aware of most of the content. Some thoughts:

He didn't mention fine tuning the torque on the action screws. I read an article on how shooters discovered that certain savage rifles responded favorably to a dialing in the torque.

https://www.accurateshooter.com/technical-articles/savage-action-screw-torque-tuning/

A Ruger 10-22 with a heavy barrel without the front barrel strap and some barrel contact in front will respond favorably to a particular screw torque to its lone action screw.

I don't know about others but every hunting/target rifle I shoot uses a specific torque.

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The BOSS system works well but is UGLY! My friend has two. One is a 223. He buys bulk ammo at the gunshows and tunes the BOSS to the ammo.

IIRC the pre 64 model 70s came with a fore end screw. I think it might be interesting to make a small machined platform that conforms to barrel with a screw in the fore end. Could be interesting to see if it could be tuned.

As to short stiff barrels. Virgil King the owner of the Houston Warehouse where he did his shooting was able to learn what worked and what didn't in a perfect shooting environment. One quote from the article talks about barrel length:


I am certain only the most fanatical would want to duplicate all he did. Virgil believes, more valuable than a little advice Jim Gilmore passed along. Jim said a barrel MUST be 21 3/4" long for optimum accuracy. That precise length, he stated, sets up a vibration pattern that duplicates well from shot to shot. Virgil faithfully followed that advice on his guns.

If someone wants to read what happened in that warehouse here is the link:

http://2poqx8tjzgi65olp24je4x4n-wpe...-shooting-magazine-special-edition-1-1993.pdf

 

[5.56×250]

Being a hopeless tinkerer and never accepting some manufacturers finished product as good enough, I've stiffened several plastic stocks over the years. I like to use aluminum bar stock. Depending on the stock depth, I will use 1/4 to 1/2" thick by 2" wide bar and cut the width to fit however much I hog out in the forearm. I drill many holes or divets all along the forearm and rough the aluminum bar up as well as drill holes in it. I haven't found any particular epoxy that I'm faithful to yet , but one that seems to work well is one of the plastic mender or plastic weld epoxies. If I dont use that, I use the slowest set epoxy I can get ahold of. I then wrap the barrel in several layers of masking tape and use release agent on the action and recoil lug. Pour a bed of epoxy in the channel, push the bar stock into the epoxy till it almost bottoms out in the forearm. I then pour more epoxy on top of the bar stock. Next , I set the barreled action back in the stock and tighten it down. Epoxy will come out around the barrel channel if you used enough. I wait till it soft sets and carefully cut the epoxy flush along the sides of the barrel. Once hard set, I pop the barreled action out, remove the layers of tape from the barrel . Now the barrel channel has a clean , even float job AND a forearm that does not move.

 

[FEENIX]

Recoil doesnt have anywhere to go, so the gun absorbs ALL of it. Magnums have been known to break stocks.

Yep! The weakest point will give in. I still use the sled except without weights.

 

[J E Custom]

Barrel Whip is not necessarily bad as long as it is consistent. The problem when anything changes,( your load, SDs, grip, position, velocity, ETC) your accuracy an/or zero goes out the window.

There are many ways to prevent this that have been discussed that work. the main advantage to eliminating/minimizing Barrel whip is better consistency, easier load development and longevity of stocks and bedding,

Many don't realize how much a barrel can/will deflect if not dealt with and eliminated. Here is a video that shows how much a barrel can bend/deflect or whip.



High speed cameras can capture these anomalies if the rifle is restrained, but be careful not to restrain it to much or you could damage it. I recommended that If you use a Lead sled, Don't add any weight to it. In the video we did in order to hold the rifles steady for the camera during firing but on the 300 rum we stopped testing to prevent braking the stock when we saw that the heavy barrel stopped flexing and the stock started taking the forces.

Whipping is not the only thing that happens to a very light contour or long barrel. Torque placed on the barrel by the bullet being rotated down the barrel actually twist the barrel counter to the twist. This occurs when the barrel contour is to light for the bullet weight used.(The heavier the bullet, the more torquing/twisting of the barrel)

You will never see a #2 taper on a bench rest rifle But you will also never see a bench rest rifle in a mountain pack ether. The pendulum swings both ways and one has to chose where he needs to be for best performance to him and his needs.

J E CUSTOM

 

[no1cr500racer]

Recoil doesnt have anywhere to go, so the gun absorbs ALL of it. Magnums have been known to break stocks.

So, if I use a lead sled to sight in my rifle, will the POI be different out in the field for the same distance?

 

[Frog4aday]

Yes. The lead sled won't "give" like your shoulder. That will cause the gun to recoil differently, changing the POI. How much? You'd have to experiment.

 

[5.56×250]

So, if I use a lead sled to sight in my rifle, will the POI be different out in the field for the same distance?

I think how much it affects the POI is based on how heavy your rifle recoils. Light recoiling rifles that dont move much against your shoulder shouldn't have a POI shift that's anywhere near as bad as a thumper, but there will be at least some shift even with the light caliber.

 

[J E Custom]

So, if I use a lead sled to sight in my rifle, will the POI be different out in the field for the same distance?

In my opinion "NO" Normally the bullet has left the barrel before the rifle reacts to recoil. The difference In POI shifts are normally the Inconsistency in the shooters hold/position. The lead sled is a good tool for testing the accuracy of your loads and the rifle. once you get the desired accuracy, it is recommended that you shoot the rifle like you would hunt with it to verify the zero. If you are not adding stress to the rifle because of your position, there should be little if any change in zero.

J E CUSTOM