A Question For The Experts...

A

AZUARO

New member
We shot our last match of the season yesterday Oct 1...The conditions were NO wind which was nice, but then it was too cloudy and we had a drastic drop in temperature from 62-64 F to 32 F before we had a little snow (.1 of an inch or so) ...All of this happened in less than 1 - 1.5 hours...

I was shooting a HV RAW TM-1000 and with these conditions and not so good shooting I ended the very good trend and success I had with this gun this short season, nevertheless I was not able to figure out what happened or why and let me explain:
  • Temperature was 64 F when we started shooting the first card...I had a chrono for adjusting and checking velocity/consistency after cleaning and doing some maintenance on hammer, hammer spring, valve, etc...
  • Adjusted to usual velocity with sighters before shooting card and the velocity consistency was there at 64-65 F, the gun was dead on.
  • Temperature dropped to around 47 F while shooting card number 1 ...The natural light dimmed rapidly with clouds getting darker (first 20 minutes), velocity only dropped about 5 fps with this 18 degree drop in temperature...Gun started to shoot a little low and slightly left when the very little wind we had was coming from LEFT at around 2 MPH. Under normal conditions and 1-3 MPH winds this particular gun remains dead on and it has a very large sweet spot (velocity)
  • Temperature dropped even more during 3rd card and we had a little snow at 32 F...velocity on gun remained the same as when 47 F...So from 65 to 32 F velocity dropped an average of 5-7 fps..With sized-weighted pellets this RAW usually shoots within 2-3 fps very consistently....
  • At 32 F when it started to snow, the gun corrected itself from shooting slightly low and to the left and came back to shooting dead on (as sighted in)...The flags indicated about the very same conditions for all targets so wind was never an issue (very little wind at 1-3 MPH coming from 9-10 o'clock)

I haven't been able to figure our what happened (shooting low to the left) and I wonder if the gun was a actually not affected and it was the scope what changed the POI while the internals adjusted to the temperature???...I unfortunately didn't check the parallax when the gun was shooting low so I don't know if this could've been the issue...
The scope is a Leupold Comp 40 X with matched lens from the custom shop and has been very repeatable, reliable and very stable when used for BR and for Field Target shooting at different temps (I have used the very same tape on the parallax wheel and have never had a parallax issue during the winter-summer seasons).

Note: Today I checked the gun with another full card at 55 F...The gun is dead on with no issues and velocity is back to within 2-3 fps from how it was at 65 F yesterday.

Any ideas or insights from the experts?

Best regards,

AZ

PS. We will not be shooting in MT until late April early May next year (snow allowing)...I will be heading south to warmer temps. soon, getting old and cold weather don't get along very well anymore
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I am thinking just the light changes were giving you the fits. yep light changes do affect scopes, not as pronounced as irons but its there just the same. I know that my zero is going to be different at 8am than at 12 pm and again change around 4 pm just from the sun traveling over head. There is an old saying about light conditions and your sight picture- at the moment my old noggin can't put it together, I think it went sun up sights down and sundown sights up , I could have that reversed. at any rate as the light intensity shifts so does your zero enough to miss that 1/16" dot at 25 meters. at 600 yards it can take you out of the x ring which would be a 3" shift if you are dead nuts centered. In silly wet the sun affect is quite pronounced. Even with cloudy conditions you still have mirage to deal with. Then we can get into atmospheric density shifts just to add a bit of icing on the cake. I have extremely sensitive flags that will pick up thermals that most flags would not even quiver in. Even at 37 degs and cloudy there are still thermals. Now if i could just put all this together during a match it would be great but I always seem to forget parts along the way.
 
AZ, I’m by no means in your league, so forgive me if I sound foolish but things to think about, is it a sleeved barrel? And or are the scope mounts of a different metal than the aluminum of scope and action?, also is stock walnut or laminate these can all effect P.O.I. I live in MI. And have shot in some similar drastic Temp changes within a shooting session( normally with gusts of wind, front moving in!) but I’ve experienced similar issues w/my RAW, mine is all stock though, just throwing un-educated ideas out there!
 
AZ
i know for a fact that temperatures affect harmonics
i'm a beginner and i have seen it
is this what you are hinting at ?
 
I don't think anybody has actually studied this well enough to know but either the rifle or the scope or both changed with the temperature. I doesn't take much change to get the results you saw. Blades mentioned the light and that very likely played a part as well. Why it is and what it is doesn't really matter in the least as long as you know it can happen. Pretty sure that's one reason scopes are adjustable. Thankfully, it doesn't happen much between shots...but it can be "happening" during a 20 minute target. I don't know anything about air rifles but the effects you speak of seem to be magnified when shooting a 25 bull rimfire target. Often, where you hold in the beginning changes quite a bit near the end....same condition...or seemingly the same.
 
With change in air temperature, air density changes, humidity changes, and velocity probably changes too resulting in change in drag and who knows. Maybe the brilliance of the sun or lack thereof affects your POI too. Further, the temperature change will reduce the bore diameter and alter the pellet drag/velocity. This can go on and on.
 
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Thank you all for your very positive good replies...

Scope, rings and action block are all aluminum with similar or very close thermal expansion coefficients....Stock is French Walnut very well sealed and prepared for BR and the barrel is not the original Poly but has the original RAW ported sleeve that came with the Poly barrel and it is bonded perfectly centered with bedding acraglass...

I shot a 250 first target paying attention but not struggling much, but then I struggled much to keep the pellets close enough to the 10 ring for scoring 10's or X's (next 3 targets),,The conditions were optimal with no wind...The temperature dropped 30 degrees in between the first and sixth target (1.5 to 2 hours) ...On the 5th target at around 35 F the gun became alive again and was dead on (shot a 249-15) and the very last card on the second relay the gun shot a very good 250-18X card...I used a chrono for all shots because after working on some internals it was necessary for checking consistency (I usually get stats from 100 or more shots).

The issue I haven't been able to even get close to figuring out is why is it that the gun shot very well at 65 and 32 F but didn't shoot at temperatures in between (shot low and to the left) ...The first card had good lighting conditions, targets 2 to 6 were shot with darker conditions but the good targets (5 and 6) tell me that the issue was most likely not the low light.

What Dick says (Harmonics changing with temperature) is one variable that intrigues me and it could very well be the problem, but I don't have enough data nor experience to support this thesis and I don't even know if the problem in my gun is repeatable or if it is 100% dependent on temperature...If you have more insights on this Dick, please step in and illustrate us.
Air density and humidity definitely changed as temperature dropped, I could feel it, nevertheless the chrono indicated an average of 5 fps or so variation in velocity for all cards.

Again, thank you all form your inputs...I am one of those nuts who want to have an explanation for everything (learning) but many times some issues are hard to explain.

Best regards for all,

AZ
 
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Pretty sure this is just one of them "things". You can come up with an explanation but it will likely be wrong. The deal is that you and your rifle may not experience such an incident as many times as others and all will be good in the end.
 
You have experienced some drastic changes in temperature and other atmospheric changes. Everything is moving including scope, action, barrel, stock, valve, lubricant viscosity, action lock time, scope dimensions, trigger finger dexterity, brain activity, and on and on. All these work as a system, sometimes in concert with each other, and others not. I doubt you can pinpoint one of these things as the source of your problem. When you get if figured out, let me know.
 
Scrench:

For this particular gun I use 13.4's or 10.3's...It shoots the same with either, but 13.4's seem to cope a little better when the wind is blowing hard, otherwise I like the 10.34's better...This gun also shoots 8.4's very precise but this weight is too light for most conditions even at 19.5 ft./lb.

Please take note that this RAW TM-1000 is using a custom 20+ year old Shilen Ratchet barrel and not the traditional LW Polygon where 13.4's seem to be the only alternative...

Preparation?...Very little: JSB 13.4's I only weigh them for serious competition, otherwise straight from the tin...JSB 8.4's &10.34's I size them with pellet gauge and weigh them...

I became very proficient with the Pellet Gauge made by a friend in Texas...Before acquiring this gauge I used an optical comparator (100X with a 30"screen - Lab quality instrument) a lab laser micrometer and air gauging...All provided me the very same precision results but I am much faster using the Pellet Gauge with the added convenience that I can travel with it and size my pellets anywhere (It takes me about 65-70 minutes to size a 500 pellet tin and about an hour to weigh them).
I tried washing, washing and lubing and both of these combined with a sizer with several die options...It didn't work in any of my guns and worse: Accuracy actually deteriorated

Washing, lubing or using a sizing die?
Die Sizing: Pellets are always sized when loaded into the chamber (pushed into the leade/rifling) so at 20 ft./lb. energy, sizing them with a die that is the same diameter as the lead makes no difference...It makes a difference when shooting ISSF at velocities of around 570 fps with 7.9's or lower velocities with 8.4's...But it makes no difference at 12 ft./lb. or 20 ft./lb and if the sizing is not to the right diameter, it deteriorates accuracy at any power level....
For ISSF I use RWS 10 Match Plus in the Black plastic box and those you don't need to size nor weigh.
Washing: I've found that it is a waste of time for me with the added inconvenience that pellets oxidize and turn white much faster.
Lubing: I've found no justification for replacing the pellet lube used at the factory...I clean my barrels after every card so claims about lead dust and factory's lube getting barrels dirty is transparent to me.
Note: These 3 steps above are controversial as there are tons of gizmos out there and many people swearing by them...So my best advice is to experiment what works for you and if something shoots better or makes you feel that you shoot better, by all means go for it.


Regards,

AZ
 
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more important to inspect for visual deformities and perhaps bits of crud clinging to to or inside skirt area. Pellets are quite a bit more uniform now days than in the past. Plus the actual amalgamation of the pellet material has changed over the years as well.
 
Thank you all for giving me some of your hard-earned advice, and I apologize for distracting the thread from AZ's original question. But if I could indulge just one more moment.

I am new to the BR game, am just now getting it started in our club, and just bought the same gun, used, a RAW TM1000 because I saw it winning 25 meter competitions all over the world. I'm a little confused though, wondering what to do, because I'm using AA Diabolo Field 10.3 g. pellets, and sometimes it will shoot 3-4 one-holers, then out of nowhere toss a few out in random directions. I have never cleaned the barrel and just asked a friend of mine who took 3rd in the FT World Championship for advice. He told me to clean the barrel VERY often with Slick 50, weigh, match head sizes, and lube the pellets with Slick 50, then try to find the sweet spot in the barrel between cleanings when the barrel is leaded in just right, shoot the competition targets then, then clean the barrel again and repeat, never varying from that routine.

Also, I don't know what this means, but I'm consistently shooting around 220-230 per card at 25 meters, but out at 50 meters, it seems like this combination wants nothing to do with it. I can't even shoot 1' groups, but it tightens up again at 75 yards. Should I consider the pellet I'm using, since it does shoot one-holers, the best pellet for the gun and figure the fliers are a dirty barrel and lack of pellet prep (which I've just been pulling randomly out of the tin), or should I continue to search for a better pellet?

As you all have experienced, nothing is more frustrating on a dead-calm day to have your dot exactly centered, execute flawlessly, shoot a few X's, then wham, out of nowhere you start shooting 8's and even 7's! Why?????

Thank You so Much!

Scrench
 
Scrench said:
Thank you all for giving me some of your hard-earned advice, and I apologize for distracting the thread from AZ's original question. But if I could indulge just one more moment.

I am new to the BR game, am just now getting it started in our club, and just bought the same gun, used, a RAW TM1000 because I saw it winning 25 meter competitions all over the world. I'm a little confused though, wondering what to do, because I'm using AA Diabolo Field 10.3 g. pellets, and sometimes it will shoot 3-4 one-holers, then out of nowhere toss a few out in random directions. I have never cleaned the barrel and just asked a friend of mine who took 3rd in the FT World Championship for advice. He told me to clean the barrel VERY often with Slick 50, weigh, match head sizes, and lube the pellets with Slick 50, then try to find the sweet spot in the barrel between cleanings when the barrel is leaded in just right, shoot the competition targets then, then clean the barrel again and repeat, never varying from that routine.

Also, I don't know what this means, but I'm consistently shooting around 220-230 per card at 25 meters, but out at 50 meters, it seems like this combination wants nothing to do with it. I can't even shoot 1' groups, but it tightens up again at 75 yards. Should I consider the pellet I'm using, since it does shoot one-holers, the best pellet for the gun and figure the fliers are a dirty barrel and lack of pellet prep (which I've just been pulling randomly out of the tin), or should I continue to search for a better pellet?

As you all have experienced, nothing is more frustrating on a dead-calm day to have your dot exactly centered, execute flawlessly, shoot a few X's, then wham, out of nowhere you start shooting 8's and even 7's! Why?????

Thank You so Much!

Scrench
Click to expand...
Mirage
 
Also, scanning past threads I see that a lot of top competitors were using WD-40 to clean their barrels. Still the case, or has something such as Boomer suggested like Otis 085 CLP become a favorite?

Thank You.
 
Scrench said:
Also, scanning past threads I see that a lot of top competitors were using WD-40 to clean their barrels. Still the case, or has something such as Boomer suggested like Otis 085 CLP become a favorite?

Thank You.
Click to expand...

I kindly ask you and all members to NOT deviate the topic of this thread to GENERAL and MULTIPLE topics, this thread was created for a very specific purpose and we are still testing and trying to figure out what happened (read first post)...

About your question and with all respect:
If you like "Fashion and Trends", then use whatever makes you feel good or fashionable or follow whatever top shooters are using...If you want to clean your gun, use ANY good product that will do the job and the list is very broad...Anything from WD-40 to Hopes, Kroil, Ballistol, etc. you can even use Kerosene or detergent and soapy water if nothing else is available...
It is a fact that top shooters are not winning because of a specific bore cleaner they use...

I used Kerosene followed by soapy water and then plain water for cleaning my hunting guns once...I finished the job with a patch covered with light 3 M oil and then shot 2-3 foulers to season the barrel ...I was hunting in Africa in the middle of nowhere and there was nothing else available to clean a gun...It worked just fine...The cleaner will NOT improve your gun's accuracy nor your shooting abilities, so don't worry much about it.

Note: My only recommendation is that if you are using a Stainless Steel barrel, to stay away from products that contain Ammonia...You don't need Ammonia for an airgun barrel and If you use it and the Ammonia is not fully removed it will pit your SS barrel...

Regards,

AZ
 
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I apologize for pulling this thread off topic. The main reason I did it was because of your reputation as a shooter, and because you were using the same gun I just bought. Thank you for all of the replies, and I will butt out now.

Scrench
 
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