ANOTHER TUNE QUESTION BUT......

[SKWERLZ]

I know that while it rarely rains here, my tune goes out the window when it does- until the humidity subsides. I’d love to know exactly why.

Would be interesting how the Local BR guys deal with that here in the PNW, lots of soggy days here.

 

[Clancy]

Would be interesting how the Local BR guys deal with that here in the PNW, lots of soggy days here.

Probably not as drastic as what we see. It may not rain for 2 months then we get 12” in 2 days. I’d still like to know. I’m going to load .3 up and down in some extra brass and have them waiting for the next rain.

 

[K22]

While I do not shoot to the level of most competitors on this Forum, I can tell you that from a varmint hunting standpoint where precision is a significant factor, it's the environmental factors that create the most challenge for me.

Wind and mirage definitely affect POI. Temperature (changes in air density) also can play a role. Even during my range practice sessions, these are the limiting factors in my ability to place a shot where I desire.

I do my load development on calm, overcast, and moderate temperature days so I can at least have confidence that the load is capable. But after that it the environmental factors and my ability to execute proper marksmanship fundamentals consistently that determines the level of my performance results.

 

[Bill Norris]

Bill, I might make one more response. In clarification, please forgive me for referring to air rifles. I realize its apples to oranges! In addressing the so-called dead air issue, these guys often use what is referred to as an "air stripper," which is basically a redesigned brake. Like many things, some have had success and others not so much. Depends on the application. The idea is to redirect some of the muzzle blast due to such lightweight projectiles. Many lightweight pellets (10-18 gr), can easily be upset upon leaving the muzzle. For the weight of the rifle and projectile, muzzle blast becomes a big issue. Although different from air guys, some believe the difference in density and expansion of spent gases and ATM air, may warrant redirecting gases. Especially when using lightweight bullets. Many longrange guys have developed some very wide nodes using a brake. They also use heavier bullets. I realize in short range BR, thats not allowed.

Mr Morehouse is probably on to something with putting heat into the barrel. Depending on how much heat, it may even slightly evaporate some of the water in super high humidity situations. Could be enough to keep gun in tune. Spent smokeless powder gases are just over 1.5 times the density of outside air on the average day. If in a high humidity situation, the density slightly drops and the difference to spent gases is even broader. Does this have anything to do with your problem? Not sure! I personally think there are some issues like this that we often pay little attention to when searching for those tiny groups and staying in tune with crazy conditions.
Again, you posed a really good question!

Absolutely, and you bring to mind something I had not actually took into account with C F rifles. It is simply the condition of the air inside the barrel just prior to firing a shot. In differing situations of density altitude which most feel is the most critical to tune and how will the bullet react?

 

[Bill Norris]

While I do not shoot to the level of most competitors on this Forum, I can tell you that from a varmint hunting standpoint where precision is a significant factor, it's the environmental factors that create the most challenge for me.

Wind and mirage definitely affect POI. Temperature (changes in air density) also can play a role. Even during my range practice sessions, these are the limiting factors in my ability to place a shot where I desire.

I do my load development on calm, overcast, and moderate temperature days so I can at least have confidence that the load is capable. But after that it the environmental factors and my ability to execute proper marksmanship fundamentals consistently that determines the level of my performance results.

I agree it does pay to try and pick the conditions when working up a new load.