Reduce Vibes/Relieve Action

[Longrange57]

Not for everyone, but it works! I'm placing under 6.5 thread, but will also include other calibers. After 140 groups with 6.5 x 47 and 6Dasher, aggs at 300 yds are .220 inch better for 6.5 x 47 and .197 inch better for Dasher. Both barreled actions shot well in conventional Revolution benchrest stock at just over 1 inch groups. When moved over to the stabilized stock and action floated, groups got smaller. Example loads....6.5 x 47, 450 primer...123 smk and Varget, 130 Berger and H4350. Also shot Factory Lapua 123 ammo. Same loads in each stock.
Dasher was shot with Berger 105 and Varget and 205 primer. Nothing was changed except the stock.
The groups I'm posting were from last week at 200 yards with 6.5 x 47 and 123 SMK. You will see it agg'd .592 inch for 5 groups. I often struggled to shoot that good with my PPC not many years ago. I will be testing a new 22 inch barreled action in 6.5 x 47 in a couple of weeks. I only have about 6-7 groups so far with each stock at 500 yards that is also an improvement with both calibers....6.5 x 47 .203 inch better with groups at 2.150 inches and Dasher improved by .256 inch at 2.030 agg. These are noticeable differences across 2 calibers, 2 barrels, 4 different loads, 4 different bullets, and 3 powders. Just in prototype stages right now. When muzzle movement is reduced, groups tighten up. The 6.5 x 47 combination with 28 inch 1.25 straight barrel weighs 18 lb, but can easily be reduced. The 26 inch barrel Dasher is slightly lighter.

 

[CharlieNC]

Interesting but it's not exactly clear what you have done, care to elaborate?

 

[Longrange57]

Interesting but it's not exactly clear what you have done, care to elaborate?

Sorry, didn't realize pics were small. I'll repost pics later. It does essentially what a long barrel block would do. The collars attach the barrel to the wood stock which acts as a dampener. On the long barrel, I have about 12 inches past front collar. On short barrel only about 6 inches. It takes muzzle movement down to virtually nothing. I won't bore everyone with slo-mo and counting pixels, but typically you can have .001-.005" movement at muzzle with convention setup. From shot to shot this is a slightly different angle. The action is free floated. The clamps are placed approximately where most of the harmonics are at. I have a 6 inch barrel block gun that shoots really well with 6 different 1.25 straight barreled actions, so I decided to see if there is any benefit to having even more stabilization. It appears from what you see in OP that its working. Its not for every discipline due to rules, but where allowed, I would think with my current work, it could help agg's.

 

[Longrange57]

see if this helps

 

[CharlieNC]

Thx, I wasn't quite sure from the original pics which the recent ones and description clarify. Have you experimented with distance of the block to the muzzle, etc? Seems like this mounting approach would limit the ability to optimize the load relative to utilizing positive compensation?

 

[Jonnyofalltrades]

Very interesting.
Thanks for sharing.
I've always had a weakness for barrel blocks, and this is an interesting twist on the idea.

 

[Longrange57]

Thx, I wasn't quite sure from the original pics which the recent ones and description clarify. Have you experimented with distance of the block to the muzzle, etc? Seems like this mounting approach would limit the ability to optimize the load relative to utilizing positive compensation?

On the barrel block gun (6Dasher), I would have about 18" of barrel that would vibrate. Remember the action is floated, so it vibrates as well. I noticed years ago that I did not have as much vertical stringing. I still run ladder test to develop loads.
With this new setup, 12" of barrel is out front with 28", very little movement! You are right in that its much harder to develop load from ladder. When installing the Dasher 26" barrel, only 10" and it basically starts to become, "pick your velocity" because it groups very well with different loads. ES now becomes the big deal.
I will firm up more of this with new 22" barreled action I will install next week. Another example is factory Lapua 123 gr ammo. Shoots fairly well in conventional setup. However, shoots really well in this new rig because ES is good. I will send a document I put together for some folks. Any control of vertical movement from harmonics will help when dealing with long distance as you well know. This is a little experiment more for myself than anything. We must keep in mind that from shot to shot vibes are not exactly the same, nor is the load, the shooter, etc. However, vibration/harmonics is something that we have some control over.

 

[Longrange57]

See Attachment

 

[CharlieNC]

Many think just shoot and let the target tell you what is best, who cares why? Then what do you do if the results are not satisfactory? This is another example regarding the understanding of positive compensation etc which provides the opportunity to utilize the physical fundamentals to eventually optimize the design of the barrel contour, stock interface, tuner, etc system for enhanced accuracy.

 

[Longrange57]

Many think just shoot and let the target tell you what is best, who cares why? Then what do you do if the results are not satisfactory? This is another example regarding the understanding of positive compensation etc which provides the opportunity to utilize the physical fundamentals to eventually optimize the design of the barrel contour, stock interface, tuner, etc system for enhanced accuracy.

I agree! More often than not, we want to blame the conditions for the large group or 1 shot that didn't stay in. I've done that. However, we never blame the little group on anything except that fact we did everything perfect. When you have a large sample size, that tells the story across similar conditions. I've shot short barrel rifles at 1,000 yds with a chrono and fast bullets print high....slow bullets print low. Not often, but I've taken my 30-32 inch rifles at same range, same conditions, same distance and witnessed slow bullets hitting high and fast bullets hitting low. We can get into all the physics we want, but the fact remains that bullet exit time can be more consistent when we stabilize the barrel. You don't get much more consistent than a rail gun that has no harmonics to speak of. Shoot one at 300 yards and the fast bullet will be high.
Lets say that 1/2 moa is about normal for 1,000 yard shooting across a number of targets. That means some are small and some are large. For every 2.5" group, you might have a 7.5" group. I would love to be able to do that, but I'm not that good. For those who are that good, it would be nice if groups were more like 3.5-6.5". We simply do not want to admit that small groups are often an anomaly. If we are honest with ourselves, consistency is better than a small group once or twice a year. I hope I don't step on any toes by using this analogy. Most folks have their program and won't change anything. I'm just playing around and having fun!
Harmonics are real and are never the same!

 

[Longrange57]

Update
Looks like this deal is doing the job. Many of you guys shoot better, but it was the comparison I'm looking for. The 22 inch barreled action will be a shooter. Shows great promise with RL15.5
All 6.5 x 47 data you see here is with 450 primer. Some 3 sh gr looked really good with 205 primer and RL 15.5. I will try 6.5 x 284 and 7-08 barreled actions next. I could say a lot more but its late and I'll let you absorb what I attached.

 

[Longrange57]

22 inch barrel

 

[Skunce]

that

 

[Longrange57]

Found some anomalies where weight of action and scope being free-floated, causes very slight movement of rifle, therefore, front bag can be tightened and alleviate some rifle movement, but the fix again, is 4 oz. of wt at muzzle. We found approx. 8 thou movement at end of action and once counteracted by wt on muzzle, groups shrink once again. We are shooting small groups of 1/4, and in some cases much less at 100/300 with 107 smk, 123, smk/lapua, 300 vld, and 140 Hyb. Although the muzzle is not moving due to harmonics, the entire rifle wants to move. The fix is the same as the tuner folks like Ezell and others. Only takes 4 oz. and everything settles down. Again, not for everyone. Has been quite a project, but well worth it. Several top BR guys witnessed some incredibly small 3 sh gr ....6 in a row, all in the o's.... (.020--.084). Many of you guys can do this with what you currently have, but this gun does it at various loads and everything is dependent upon extreme spread. Factory Lapua 123 shoots like a handload. Most of the time it has a spread of 4-15, which that's where most of my handloads are, smaller the spread, smaller the group.
Not for everyone but fun to research.

 

[Longrange57]

4 oz. did the trick!

 

[Ron Gorski]

4 oz. did the trick!

How did you make the clamps or did you just buy them?

 

[Longrange57]

I've made them before, but easier to buy them if using a straight taper barrel. Ruland, Climax, Dayton, Speedway, and many others make various types of clamps. Ruland has some really nice stuff and different sizes. If using a tapered barrel I've special ordered them before. That was years ago in 22LR configuration.

 

[Longrange57]

I've used the mountable collars from Ruland more than anything. The thick ones on this barrel come from Speedway because they just happened to be 1.25 OD.

 

[357Mag]

I've used the mountable collars from Ruland more than anything. The thick ones on this barrel come from Speedway because they just happened to be 1.25 OD.

Longrange -

Howdy !

Another method.....for barrel " clamp " along w/ " floated" action.
See pics, below...

With regards,
357Mag

 

[357Mag]

Longrange -

On the range....

Regards,
357Mag