Adding a fixed barrel weight.

[RAVEN]

Cam my original 1.25 Krieger that Giles put together for me back in 2002 -2003 had a Vaas Muzzle break fitted doh anyway can’t use it in F-Class I did a ladder test with it on and off and ended up with a barrel node over 1.5gr as opposed to 2 X nodes with .5 spread.
Hadn’t really thought much about it but now understanding that a gun that is in tune more often is the one to use taking in atmosphere variations powder lot etc. etc.
BTW the break weight is approx 250grams

[Cameron Mc]

We never stop learning hey Richard. My muzzle weights range from 500 to 700grams.

[KHGS]

For what it is worth I agree with Cameron, I prefer a static weight. Many tuners are too light, the weight has to be in relation to barrel weight & length. Short stiff barrels will require more weight. What is the ideal weight/barrel relationship? Damned if I know, but I recon Cameron is pretty close to the mark.
Keith H.

[RAVEN]

Cam how is the balance of your rifle from memory you use heavy Vamint or MTU's?
RB

[DaveMc]

As another example - I had a fixed weight done based on Cams and Marty's observations. 900g on the end of a 30 inch Krieger HV barrel (it is huge). This has the same balance as my 32 inch straight 1.25 inch barrels and my rifle is set up for it. The weight extends past the barrel by an inch.

That barrel also has a sweet spot of about a grain. Adding the weight brought the sweet spot to the same point as my other barrels so I also could use one load. I used this barrel from 300-800 yards in the Nationals last year Denis and took it to the FCWC's Lewis (You couldn't have missed it - is the mother of all barrel weights). If I was going to tune it I was simply going to turn some more off in the lathe. But it was fine as it is. Just adding a big terminal weight seems to "dampen" vibrations substantially.

I agree with Keith - the thicker/stiffer/shorter the barrel the heavier the weight probably should be. I guess we have headed as far from the "can't swing that sort of barrel length or weight off an action and bedding" as we could and with little observed issues - We have either glued in actions or Barnards on Al bedding blocks. (Keith - your thoughts or observations and experience on this would be greatly appreciated).

There was something on the net with 22 barrels (Border barrels??) where you could model the barrel tapers and watch the vibrations and some of the machining software has this feature. A reverse taper barrel had some interesting characteristics. I am guessing from what we have seen and modeled that the bigger the weight the better the damping effect.

Just another point. Try playing with your seating depth if the node isn't wide enough. Sometimes this helps.

[Cameron Mc]

Cam how is the balance of your rifle from memory you use heavy Vamint or MTU's?
RB

Richard, I used Heavy Varmint barrels mainly.
I have a brass rod in the butt of the rifle for balance point just in front of action.

Cheers

[Brad Y]

Denis

The other thing you could look at experimenting with is a barrel stretcher tube system, similar to what Jeff Rogers runs up there in Qld for his 1000yd BR rigs. Its supposed to stiffen the barrel and make the accuracy nodes alot wider. Some people I have spoken to reckon its turns a gun into a choose your speed and shoot small groups with it sort of thing, but I havent heard any of this happening very consistently. Matt Paroz experimented with one years ago and from talking to him I gathered that he probably wouldn't do it again.

But the heavy weight on the end of my 1.25 straight krieger seems to have helped so far and I havent had the opportunity to adjust it. Its zero setting is just forward of the crown and will wind a good 20mm forward quite easy.

Erik Cortina has a couple of threads on accurateshooter.com where he and Steve Blair use barrel tuners. They tune powder charge at 100m and work on loads with good vertical. Then they adjust seating depth to see what depths consistently shoot good groups at 100m, then use a tuner (very small and light considering barrel size) to adjust group shape. I cant vouch that I have seen the results in person but the photos they show of group shapes do show that the tuner is having an effect. They say that their loads from this process generally work very well at 1000yds and while they dont "set and forget" after setting the tuner, they do treat it as a solid barrel thereafter and dont change it unless the gun goes out of tune. I see Steve is usually up there in results at most shoots so that is encouraging for this process. The only other thing they do before settling on the load is chronographing to make sure they have a good ES for consistent long range shooting which is good to do anyway.

Im lookng forward to adjusting my tuner/dampener weight further past the crown of the barrel to see if I can change/improve group size and shape at 100 or 300m and have it carry out to 1000yds.

[RAVEN]

Brad I prefer to do all my group testing at 300m I have had other rifles that shoot better group at 300 than 100 its to do with gas disturbance with boat tail bullets.
What I look for is the carbon ring around the bullet punched hole a tuned load will display very even carbon which makes the hole in the paper look small BTW I use yellow 500 fly targets to do this light weight card good contrast.
RB

[mike H]

At the risk of reading something into the previous posts,that was not said,or jumping to false conclusions,I have to ask the question.If the sweet spot/tolerance was say 0.5 grains from top to bottom and you loaded ammo in the middle,giving 0.25 grains either side,would you bother loading to the closest kernel of powder as some do,or tolerate perhaps a 0.1 grain either side of the nominal load? Measuring powder has become a chore and anything to give my eyes a spell as well as speed up loading would be welcomed.

Mike.

[Brad Y]

Richard, I agree it seems boat tail bullets really perform at 300 and further. But the odd time I have seen them beautiful at 100m. My 260 is one example. I would have no issue at having a crack at 100/200 benchrest score shooting with it.

I personally did all my load work at 900m before this method, and after trying 100m a bit, it seems 300m just seems easier to read. The short range accuracy of most well built f class rifles doesnt tell much when reading groups. 300m on an ET is very good for load work.

[RAVEN]

Mike I wanted to do a velocity check on one of my barrels the other day
so I loaded from 52.6 - 55.0gr behind 180VLD a father & son visitor turned up at the club so I allowed them to fire off these rounds at 300m dropped one point I coached of coarse may have been a different result if this was shot at 900m

Broadly speaking when I look at result I always look for the person with the highest X count this generally will be the most accurate rifle & load.

So a reasonable assumption maybe that short range load testing may not translate to long range accuracy.

And if you have a wide node trowing charges would be ok
But I will always weigh to achieve the most consistent powder charge


interesting hu
RB

[mike H]

Thanks Raven,
More of a hypothetical question,I couldn't change my ways now.
Mike.

[RAVEN]

Mike if it's not broke don't need to fix it

[Cameron Mc]

At the risk of reading something into the previous posts,that was not said,or jumping to false conclusions,I have to ask the question.If the sweet spot/tolerance was say 0.5 grains from top to bottom and you loaded ammo in the middle,giving 0.25 grains either side,would you bother loading to the closest kernel of powder as some do,or tolerate perhaps a 0.1 grain either side of the nominal load? Measuring powder has become a chore and anything to give my eyes a spell as well as speed up loading would be welcomed.

Mike.

Mike
The advantage of a wide node is it allows for variations in powder lots.
I weigh every charge like most others. As you go to another bottle of powder it's burning rate may be equivalent to say 0.5 grain faster or slower. So the wide node will now keep your accuracy where it should be.
Hope that makes sense.

Cheers

[mike H]

Cam,
Makes sense to me.
Thanks,
Mike.