vertical stringing

[woodnut]

I got to shoot my Bergara barreled Encore today. Very disappointing! Nothing but vertical stringing; and I mean three inches or more! I know the scope in on tight and it's a fine Zeiss. I'm shooting 110 gr. by vol. of BH209 and a Boat tailed 250 gr. Barnes with a blue sabot. Win 209 primers. Not the Win 7 primers. Tried another bullet and sabot , no change. I also shot 100 gr. BH209 with the Barnes and got a little better. Do you think I'm just not at the sweet spot in the charge? Oh, and no horizontal dispersion at all. I don't shoot this bad and neither should the Encore. It has a wonderful trigger and hing pin. It's tight. Any one suffer this before? What's up ?

 

[FrontierGander]

could be barrel heat, i get that when i dont let the barrel cool down.

Does the hinge pin fit tight in the barrel lug itself? Remove the barrel and run it through the frame first, and then try the barrel lug. I had one that fit the frame real good but going through the barrel it was loose.

 

[ENCORE]

could be barrel heat, i get that when i dont let the barrel cool down.

Does the hinge pin fit tight in the barrel lug itself? Remove the barrel and run it through the frame first, and then try the barrel lug. I had one that fit the frame real good but going through the barrel it was loose.

Very good advice.

If the fit in the barrel is to loose, it can be a contributing factor. If it is, then I would suggest you visit Mike's site and purchase the proper reamer. Mike Bellm TCs - Tools, Hinge Pin Reamers, Misc

You would be VERY wise to purchase the HD locking bolt spring from Mike also.

Check the mount carefully again. Make sure its tight and loc-tited down with BLUE. There's also the remote possibility of springboarding.

 

[woodnut]

Encore, what's springboarding? And what is the HD locking bolt spring? I will double check the pin; but it shot great with the 20 TAC so I doubt that's it. I am positive the mount and scope are good. And yes, blue was used on the mount. All good advise from both of you!Thanks

 

[woodnut]

I just realized the new barrel doesn't have the same hole for the pin. Duh. I will check it. ( Hate getting old!)

 

[ENCORE]

I just realized the new barrel doesn't have the same hole for the pin. Duh. I will check it. ( Hate getting old!)

Getting old just gives you more experience and our minds are working so fast, that sometimes we can't keep up with it. That's my reasoning behind it and I'm sticking to it.

Thank God you don't have the FLU......... that both the wife and I picked up. After having the shot back in October!!

 

[ENCORE]

Encore, what's springboarding? And what is the HD locking bolt spring? I will double check the pin; but it shot great with the 20 TAC so I doubt that's it. I am positive the mount and scope are good. And yes, blue was used on the mount. All good advise from both of you!Thanks

Bear with me here.... its hard to concentrate, let alone type. But, in my moments of clarity with this flu, this does give me something to do other than moan and groan. Thank God, as I appear to have started to get over the hump.

Springboarding..... is a term that is used when a shooter's scope and mount moves at the precise moment of ignition and prior to the bullet leaving the barrel. This is most noticeable with long range centerfire shooters. With both the Encore platform rifles and the CVA Apex, this can be a problem. Its caused by the mount over lapping the taper on the barrel. Any minute amount of space between the front mount and the barrel...... MAY.... notice I said .. MAY.. be the cause or a contributing factor. Again, this has been most noticeable with centerfire shooters. Now.. as crazy as this may sound, this is what the professionals are discussing.

I had considerable conversation with Kurt Bellm about this concern, in which he informed me that to his knowledge, I was the first to bring this to their (Bellm) attention when shooting a muzzleloader. Again, this is something that the centerfire shooter's complain of. There are a couple things that can be done to correct it, if, it is actual springboarding of the scope. Some have added another ring to their mounts. Others send in their barrels and have additional mounting screws drilled and tapped.

Kurt also explained another concern that .... MAY.... cause vertical stringing. It has to do with a slight excess in the frame for the locking bolt. I'm to darn tired to remember exact wording but, when the locking bolt locks when the rifle is closed, it there's an excess amount of space, it can also create vertical strings by the slightest of movement. NOTICE........... this can be present in ANY break open rifle. Bellm has welded and re-ground these for a tighter fit.

I spent hours on the phone with Kurt and Barnes Bullets ballistics experts over this issue. I actually got a math professor involved, who proved that the locking bolt could definitely be the cause. I experienced the issue and couldn't figure it out. I was shooting 200yds and right to left, wasn't varying 1/2" but, I was getting 2" to 2.5" vertical strings and it was driving me completely nuts.

The locking bolt spring is located on your barrel above the hinge pin. The factory spring is somewhat light, which is why Bellm sells the HD spring. Its a bugger to do by yourself. You want that pin inside a towel when you tap out the pin holding it. If not......... you'll be looking for both and you certainly don't want anyone hurt. Its just as hard or harder to install the HD spring. There's two ways, one someone drives the pin into place while you're trying to hold it in or..... you can use a very small "C" clamp which works very well. Wear eye protection.

 

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I couldn't stand it so, I made my way to the bench.

If there is in combination or either by itself, springboarding, hinge pin or locking bolt movement of .005" there can be a 13" difference, or any where in between at 200yds POI. This movement has to happen between the point of ignition and the point at which the bullet leaves the barrel.

One other point to consider also, is that shooting into a good head wind can contribute.

 

[woodnut]

Wow, Encore, this is getting deep. Sorry to hear about you and your wife coming down with the flu. I had a bad cold. My bro in law came to visit and he got something that kept him here waaaay too long. Then my wife got ill. Good news is that all of us survived. I sure hope you two will be well very soon.
Anyways, I really appreciate the info on the locking spring and all the other possible reasons for the vertical stringing. I also consulted with Allen at Harvester Sabots and a friend about this. Both offered yet another reason. The sabots! Seems some sabots are very heat sensitive and I needed more time between shots for the barrel to cool. It was 61 degrees out. Both said it could take ten or more minutes between shots.
I also believe it could quite possibly be D. all of the above. I checked the hing pin and don't believe that's it. As for the locking spring, while I can push the bolt back by hand; I can't discern any movement in the gun when closed. Nada.
One other thing. My friend who was with me said the barrel "jumped" differently at some shots. Higher or not as much. I could be guilty of having a slightly different pressure on the stock.

 

[ENCORE]

Thanks woodnut. I'm definitely over the hump. The wife still has a ways to go yet. Fever has finally broke and I hope for good. I'm actually feeling much better this evening than I was this afternoon.

Years ago, people would have been happy to hit a paper plate at 100yds, even getting one or two shots into it. Its much different now. Some of the young guys have never experienced what some older muzzleloaders have went through and what's got us to this point. There are some that send hundreds or thousands of rounds through their rifles each year and we're all still trying to improve! And yes, we all want more.

I've always been one, that when l have an issue, one way or the other, I'm going to get to the bottom of it. Believe me, there's been times I didn't want to know too. I do some testing but, its when there's a problem that isn't easily resolved or, something that the shooter needs reinforced in. Sometimes to satisfy my own interests. I use precision equipment to test loading forces and bullet seating pressures to look for differences in POI. Some might say I go a little bit overboard? Well I learned a lot about what ..... MAY..... help to cause vertical strings, especially when I got the math professor involved. That stuff has long been gone from my memory....

One other thing............ just one other small but yet still a contributing factor in your quest for pin point accuracy. Order the HD hammer spring. The faster that hammer hits the pin, the less chance of even the slightest movement. I have both the 44# and the 51# spring. There's a HUGE difference from the 30# factory spring.

 

[woodnut]

Thanks, Encore, and I'm glad you're better. None of us had much if any fever. I'm staying out of crowds and acting like a (healthy) hermit!
As for the hammer spring, I concur. The faster things happen before the bullet leaves the barrel, the better. I said earlier than MGM had done their magic on it. I'm sure the hammer spring was done. It's even engraved! When I got it, it was a 20 TAC and it would shoot bug holes; just like my ARs. That's a wicked cartridge for pasture poodles and other varmints.
I am getting some different sabots from Harvester. Allen was very kind and generous and voluntarily is sending me some samples of his sabots and some bullets,too. Nice fellow. Will wait til it cools down to go shooting again. Thanks again!

 

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Are you shooting these? 50 CAL .451" 250 GR SPIT-FIRE T-EZ FB - PER 24 W/SABOTS | Barnes Bullets

These bullets with the blue sabot are the T-EZ bullets. The blue sabot is designed to load easier and the bullet has a flat base.

I shoot the 250gr TMZ which does have the boattail. Thousands of them actually. When you seat your bullets, seat them hard, with a solid THUMP using both hands. I average 105# of seating force and it is well known that BH209 needs to be seated hard. If the blue T-EZ loads easy, you may want to try the TMZ bullet with the supplied sabot.

I'm not one to try changing sabots, especially when Barnes has done most of the work. However I have tried some different and found that in every case, they never performed as well as the supplied. I just tried some Harvester Crushed Ribs this fall that a friend gave me and made for the TMZ. They opened up my group to 4"+. If your right to left is centered but, your getting vertical strings, changing sabots most likely won't by itself correct the problem.

Good shoot'n....

 

[FrontierGander]

i load my bullets with thumb pressure with bh209

The TMZ is a tough loading bullet in the Bergara barrel. I shot an accura v2 with them over a month ago with 110gr bh209 and while they shot excellent, man they were a mother to load with a solid range rod. With a factory ramrod, i would have been crying.

 

[ENCORE]

i load my bullets with thumb pressure with bh209

The TMZ is a tough loading bullet in the Bergara barrel. I shot an accura v2 with them over a month ago with 110gr bh209 and while they shot excellent, man they were a mother to load with a solid range rod. With a factory ramrod, i would have been crying.

I got the Crushed Ribs from a shooter that shoots here with the Bergara on his Pro Hunter (Bellm Barrel). After he put a couple hundred rounds through that barrel, the TMZ loads fine. He came over and took a doe at 191yds with one last month. A complete pass thru and a short trail you could follow with a Bic lighter. Another buddy shoots them out of his Accura and he had the same results but, they do load harder in his than the Bergara on the Pro Hunter.