Printable View
So I watch shooters at ranges and competitive matches on YouTube. I have a barrage of questions. Let the barrel cool between shots? Why wait like some do to chamber the cartrige? Is it as not to warm it up in the chamber prior to the shot? Is ammo temp a big deal? I see shooters taking temp readings of the barrel and the ammo. Does any of this matter under 600 yds?
Quote:
Originally Posted by powderburnz
1...i dont know what type of shooting allows cooling times between shots?
2...yes...heat will cause POI shifts...especially if your running a double base powder
3...yes ammo temp matters...hot ammo hot chamber equal higher pressures
4...it depends on how accurate you are trying to be
I try to use all the time allowed for the given match, so I try and wait,, or space out the rounds fired to not heat the barrel too much.
That being said, if I drop a point early I get mad and start shooting fast sometimes 25 shots in 12 minutes. It still shoots good when you go fast but the barrel does get real hot.lol
One thing I don't do is let a round set in a hot chamber too long,, that's called cooking the round like LongRange said it will have higher velocity and more pressure.
Here's a very interesting article about barrels, heat and FLUTED BARRELS. Page down and find the survey on who uses fluted barrels in competition.
Basically is says that Shilen will not flute a barrel because it ruins the accuracy. Also quoted is research from Accuracy International that quantifies amount of movement from POA caused by fluting and barrel heat.
http://precisionrifleblog.com/2014/1...-the-pros-use/
Quote:
Originally Posted by Texas10
Interesting. I usually shoot 3 shot groups not 5. So that should help. Also being at the range and at the mercy of other shooters having to go down range I usually only get to shoot one group at a time, I go slow. Maybe I should take temp readings to see where my barrel is at on that given day. 10fcp-sr, it is fluted.
As others have said. You want to chamber your round only when you are ready to pull the trigger because of chamber heat. This hold true starting about round 3 or 4. It makes a huge difference at 1000 yards.
If you are watching F or F/TR then the pause you may be seeing is the shooters waiting on the flags to show favorable wind conditions. It is not uncommon for all of the wind readers to be holding off for the flags to "drop" then all hell breaks loose when the wind dies down.
I have my bolt open with a round setting on the single shot tray if the conditions are not what I want, when conditions are ready I close bolt and fire. The aluminum tray doesn't get hot.
In another study, Dan, and if I can find it I'll attach it later, was a check of velocity as compared to barrel temp. IIRC, the procedure was to place a cartridge in the magazine (as you do) and then chamber and fire as quickly as practicable, measuring velocity spreads as the barrel warms. The study concluded that it was barrel temp, not cartridge temp that caused velocity spreads and that the amount of time a cartridge typically spends in the warm/hot chamber was not enough to effect powder/primer burn rates.
If I understand this principal correctly, a hotter barrel has less of a quenching effect upon the expanding gas than a cool barrel, resulting in increased velocity.
Personally, my practice is to do as you. Load and fire, usually in less than 30 seconds. I have also used an IR thermometer to track and record barrel temp vs POI and found that my fluted barrel really starts to move at about 100 F and above.
So glad autumn has finally arrived here in South Central Texas!
Great info Texan!Quote:
Originally Posted by Texas10
+1.Quote:
Originally Posted by DanSavage
I'm not sure if this first link is the study I read sometime back, but some good information on these websites.
http://archive.org/stream/velocitypr...0culv_djvu.txt
www.frfrogspad.com/intballi.htm
http://longrangeshooter.com/2009/02/...fects-on-zero/