Barrel harmonics and a Palma front sight

[hockeyref]

So I just reviewed the thread - vertical-dispersion-flat-spots-on-the-mv-ladder-test-are-meaningless,,, and re-read Varmint Al's testing (I read it years ago and forgot about it) and began wondering if\how that might be applied to my .223 Palma rifle. If I read Al's data correctly, 1- you can only tune for one distance and 2- a barrel with a tuner weight on the end was always better that a bare barrel even if the tuner was not at an optimized setting.

So..... a couple things started bouncing around my head:
1- Would the effect of a tuner get lost in the noise coming from sling shooting a Palma gun vs shooting off a rest? Talking about the effects of holding the rifle (absorbing\muting vibrations) vs bag\rested vibrations of the system.
2- Assuming the tuning effect is not lost in the noise of sling shooting, could the weight and location of the barrel band and front sight assembly on a 30" Palma barrel (light Palma contour) act as a tuner as there is about 2" that my 4 ounce sight assembly can be moved back from the muzzle.
3- If #2 above is true, Is it worth tweaking the sight assembly location for 1k yard loads and if you tested\tuned at 500 yards, how far from optimum might it be at 1k?
4- If my load holds ~1/4 moa elevation at 500 yards with the sight assembly randomly bolted in place would you call it good of try to tweak further at 1k?

 

[Doug Beach]

Not in anyway trying to be a smart azz, but…
In sling shooting you need to break 15 or 20 good shots, with a good wind call for each. If you do this, you will shoot a very high score, with most any decent rifle. If you don’t, you won’t. Trigger pulling, and wind reading errors will cost you 99+% of all the points you ever drop. If you’re already beating everyone, all the time, and are just trying to figure out how to get one more X, by all means adjust that front sight location. Just remember to get it perfectly level each time you move it, or it will cost you points…
My good friend shot a 3x600 a couple weeks ago, with an iron sighted .308 Palma rifle. His score was 600-53x. He adjusts nothing, experiments with nothing, sorts nothing, load develops nothing. Same load for every barrel, in every rifle. He just shoots. Learns from his shooting and wind reading mistakes, and shoots some more.

 

[fkimble@charter.net]

Not a Palma guy, just an XTC type. But there is no barrel band on a Palma gun, and the barrel is most likely floated, so the sling and stock will not be affecting the barrel harmonics. If the barrel is releasing the bullet at the same place for each shot or tuned as some call it, the bullet grouping should keep it's relative grouping, only getting larger due to external forces such as wind. So a 1 moa at 500 should theoretically be a 1 moa at 1000. Of course we all know groups grow a little as they get farther away. Atmospheric conditions can be a a major cause of this. Barrel heat can also change the barrel harmonics, especially on a long skinny barrel.

Frank

 

[clowdis]

I do all my load development at 200 yards and it seems to translate to 1,000 yd. accuracy just fine. I use a scope on the rifle but I also leave the front sight on the rifle (install it upside down) when I test my loads. This being said there is very little load development needed for a Palma rifle. Use 46.5 grains of Varget or VV N140 under a 155 grain bullet and go shoot.

 

[Rtheurer]

So I just reviewed the thread - vertical-dispersion-flat-spots-on-the-mv-ladder-test-are-meaningless,,, and re-read Varmint Al's testing (I read it years ago and forgot about it) and began wondering if\how that might be applied to my .223 Palma rifle. If I read Al's data correctly, 1- you can only tune for one distance and 2- a barrel with a tuner weight on the end was always better that a bare barrel even if the tuner was not at an optimized setting.

So..... a couple things started bouncing around my head:
1- Would the effect of a tuner get lost in the noise coming from sling shooting a Palma gun vs shooting off a rest? Talking about the effects of holding the rifle (absorbing\muting vibrations) vs bag\rested vibrations of the system.
2- Assuming the tuning effect is not lost in the noise of sling shooting, could the weight and location of the barrel band and front sight assembly on a 30" Palma barrel (light Palma contour) act as a tuner as there is about 2" that my 4 ounce sight assembly can be moved back from the muzzle.
3- If #2 above is true, Is it worth tweaking the sight assembly location for 1k yard loads and if you tested\tuned at 500 yards, how far from optimum might it be at 1k?
4- If my load holds ~1/4 moa elevation at 500 yards with the sight assembly randomly bolted in place would you call it good of try to tweak further at 1k?

To your point #3 If my rifle shoots good at 1000 yards... it sure seems that they shoot great at 500 or 600 yards as well.
#4 Tweek at 500, test and confirm at 1000 yards and keep that tune. Thats how i do it. again you mileage may very.
The one time i went with a 34" barrel and set the front sight back away from the crown to make the proper sight radius for the team, i had no luck at all. I ended up cutting the muzzle off and running the 30" barrels I have always done. The rifle shot like crap. Moved it back out to the end and it shot much better. One thing i noticed and may or may not have any bearing, When i run a tight patch through the bore i feel a slight choke at the crown where the front sight band is.

 

[XTR]

Assumption #2 is not valid. A quarter to a half MOA wobble is pretty close to godlike from a sling shooter.

HP has a 1 MOA X-ring and a 2 MOA 10-ring. If you miss it you pointed the rifle in the wrong place. Yes, a tight shooting rifle is surely a good thing, but the trigger operator, sight dialer is what makes the difference. If your rifle will hold a quarter MOA the only reason you haven’t won the National Championship is you.

Edit: If you have the time by all means experiment. I certainly can’t tell one otherwise. Someone once told me my 600 yd score in SR might be better if I sorted brass. I knew full well that pointing the rifle in the middle was what I needed.

 

[mgdietrich]

I put 30mm sight on and off a 6dasher, shooting some with scope and some with irons. I had a 199-19@600 with irons and several 200-18’s with scope. Same load, same gun, same shooter just changing the sight system.

Feel free to test it, but the target is big. If you have a 0.5min gun I doubt you can see the result differences making it a 0.4m or 0.6m gun.

 

[ngb1787]

After the barrel is tuned, put ten shots on paper , after that take tuner off and put ten shots on paper, now compare and post photos of scores and groups on accurate shooter please.

 

[hockeyref]

OK, let me clarify some thoughts:

First - this thread is just - as I call it - "ballistic masturbation"... A "what if" or a "does this thought make sense based on that discussion\Varmint Al's research". I was wondering if the position of the front sight could possibly be utilized as one would use a tuner in load development to further tighten groups\reduce vertical. Like others, I have seen improvements in accuracy shooting scoped with a front sight or a front sight band in place. I fully realize that the wind reading skills and position\shot skills will have the biggest effect on score......


What got me thinking about this?
As part of the initial break in of my new .223 palma barrel I used my old 90JLK service rifle load seated .005 off. After shooting over a crono at 100yds I shot a 5 shot group at 500 for grins and just to see if the 90JLK's would be stable out of this barrel (shots 8-13 through the new barrel). Scoped from bench and bags the group was 2.5" high x 6" wide. 300 yard wind flag said wind was 4-7mph and was a tail wind from 12 - 2 o'clock. (shots 8-13 through the new barrel). 5 shot velocity average 2855 fps, ES 19fps, 66 degrees, 30.13hg,1000' elevation, 43% humidity. Did not calculate SD, I was only wanted an ave velocity to get on paper first shot at 500 yds. Observed windage agreed with windage calculated by JBM ballistics app.

To be quite honest, I might be perfectly comfortable just running with this load prone 500-1000 yds but would like to minimize the vertical spread further if possible.

Doug - no offense taken. Just looking at potential ways to fine tune a load. If a tuner for long range BR or F-Class is legit, why not utilize the same theories\process to help produce better LR sling loads (when developing with a scope)? And yes, "the juice is not worth the squeeze" can be a legit answer, but at what point is "good enough" reached? 1/2 moa vertical.... 1/4 moa vertical? Or do you worry more about what the crono says with low ES\SD? For service rifle I wanted consistent 1/2 moa 10 shot groups shot prone with irons off of sand bags at 500 yards in no wind conditions.

Frank - by barrel band, I meant the clamp\front sight assembly.

Clowdis - I have done the same with the front sight for any\iron matches. I test at 200 then 500 with a scope. Note that I am shooting a .223 not .308, I just put on a new barrel and I have not put on the front sight yet.

XTR - I think we are confusing sling performance with load dev from a bench. I am well versed in High Power but It's been a good 10+ years since I shot in any sort of registered comps. Was Master XC (my poor offhand and the occasional duh moments kept me from going HM). Was Expert LR and literally missed making master on my initial classification by .001% with and A2 AR service rifle.... only shot a couple LR matches a year. FYI that 6.5 twist A2 upper was one of the first uppers that Holliger built to shoot 90JLK's.

 

[gunsandgunsmithing]

The key to a tuner is the ability to make very small, adjustments, easily. Like, only a thou or so of tuner travel. So unless you can move your site in those kind of increments, repeatably, you're chasing your tail. That said, having weight at the muzzle widens the node very slightly. Not enough to hang your hat on, though.

edit....but yes, moving the front sight, or any weight at the muzzle, will tune the rifle. Again, the key is tiny increments or luck. Don't laugh...Tune repeats over and over so you can randomly hit on sweet spots. They're closer together than most would think. It'll work if you figure out how to move it say, .001 at a time.

 

[mgunderson]

In theory you could move any weight on the end of the barrel to "tune" the rifle. Tuning with and without the front sight would show you what you want. I expect there are only a few people (like that shooting stud that shot 53x) that might be able to see the results with iron sights.

 

[memilanuk]

So... a long while back, my first foray into tuners was one from down under. I think Sumo was the name. It was intended to be a slip fit for a typical 0.750 front sight tenon, using green loctite to hold it on. The tenon on my Palma rifle at the time wasn't really long enough for both the front sight and the tuner, and I made a mess of the loctite job so I ended up not really using it. Just mentioning it as a conceptual option.

Before that, I think I'd seen similar discussions on the old long-range.com forums about moving the front sight base around to affect the tune, or even if the height of the sight tunnel had an effect. From the little I remember, the consensus was that it'd be stupid difficult to move the front sight base precisely enough to actually do testing in a repeatable manner. One option floated was to use the tail of a set of calipers referenced off the muzzle to the sight base to measure things. Or use feeler gauge between the sight base and the tenon shoulder might be another option. Getting it tightened down level/plumb without shifting would be the trick, though.

Whether it actually helps enough to make the juice worth the squeeze... dunno. In theory a light or medium Palma contour barrel at 30-32" should be about as responsive to a tuner as they get. On the other hand... a 308 with 155s is so ridiculously easy to get shooting well it may not be worth the effort to dial it in further.

 

[Rtheurer]

Since its winter... Uh Hmmm..... Put your front sight on the gun. Base, and sight, put it upside down so that it hangs below your barrel this will allow you to use your scope for testing.

I agree however that those incremental moments are in such small amounts it would be almost impossible to do a proper test other than just winging it by moving loosing the band, moving it then tightening it back up.

But what the hell.. Its winter...

Good Luck

 

[hockeyref]

Hey... Gimme a break on the front sight, It only took me a year to get around to actually install the new barrel on the action....... LOL.... mounting and flipping the sight is exactly what the plan is and it'll be in place when actual development starts. I only took the gun out when I did cuz it was an abnormal 60+ degrees in December in western PA and I wanted to get some initial velocities and see if it might want to agree to shoot my stash of JLK 90's or cause me to buy bullets......

But in my defense, my plan was to get back into long range last year and things just didn't work out. I've been shooting only a local mid range match the past few years and my 26" Shilen barrel was\still is shooting really well. I just couldn't see burning up barrel life at 500 yards when it will take a year or more to get a replacement and the barrel that was on the gun is holding the x-ring on the 500 yard MR65FC target from a bipod.


It is winter and I DID say that this thread was mostly an exercise in ballistic masturbation"....

 

[Fclassfool]

Ballistic masturbation

 

[Alan Warner]

A long time ago in lands where the home folk speak English and the order of the day was they issued ammo. The incremental movements of the front sight was used to tune the ammo to the rifle. This was accomplished by either moving the front sight or chopping the barrel off in 1/8 inch increments,. Many even tuned separate rifles to be yard line specific to that ammo. Today's components and hand loading methods negate that need IMHO.

Alan

 

[hockeyref]

Alan, Very interesting.... I want to know more...

 

[gunsandgunsmithing]

Alan, Very interesting.... I want to know more...

Alan is right. I edited my post above, which might also be of help. You just need to improvise whatever you have to, to move in tiny increments. But yes, you can tune the way you're talking about. Maybe Alan will come back and elaborate on that but I think he and I are in pretty good agreement on tuners so I'd say we'll give you similar feedback.

 

[Rtheurer]

Hey... Gimme a break on the front sight, It only took me a year to get around to actually install the new barrel on the action....... LOL.... mounting and flipping the sight is exactly what the plan is and it'll be in place when actual development starts. I only took the gun out when I did cuz it was an abnormal 60+ degrees in December in western PA and I wanted to get some initial velocities and see if it might want to agree to shoot my stash of JLK 90's or cause me to buy bullets......

But in my defense, my plan was to get back into long range last year and things just didn't work out. I've been shooting only a local mid range match the past few years and my 26" Shilen barrel was\still is shooting really well. I just couldn't see burning up barrel life at 500 yards when it will take a year or more to get a replacement and the barrel that was on the gun is holding the x-ring on the 500 yard MR65FC target from a bipod.


It is winter and I DID say that this thread was mostly an exercise in ballistic masturbation"....

1 is None and Two is only one in this game. But you have already found that out. LOL

 

[hockeyref]

LOL - known this for quite a while and had a 2 rifle plus spare barrel rotation set up for service rifle. I have yet to get things properly figured out for belly shooting...... I figure that I need to order 2 or 3 .223 barrels or maybe three 308 barrels ........ at 57 years old I figure I might be about done by the time I've shot out those barrels.