Dan534 Posted February 13, 2011 Report Share Posted February 13, 2011 Has anyone noticed velocity changes after a few hundred round through a 'new' barrel. Chronoed my 6br yesterday and it was averaging 2810fps down from 2860fps on the previous testing a few months ago, same load, same charge of varget, same bullets, same chrono. Just wondered if barrels 'settle in'? Had about 500tds through barrel. I may have to adjust the load to get back to the sweet spot? Any thoughts? Link to comment Share on other sites More sharing options...
John MH Posted February 13, 2011 Report Share Posted February 13, 2011 Could be the temperature change between the time you last tested it and now? Link to comment Share on other sites More sharing options...
rabbit fingers Posted February 13, 2011 Report Share Posted February 13, 2011 Is your accuracy the same? I'd let the target decide rather than chase a velocity. You don't say what chrono you're using but are the cheaper ones that reliable? Another thing to consider is the distance from the muzzle. you'll get errant readings if you're too close and the sensors are 'seeing' powder and not the bullet. Link to comment Share on other sites More sharing options...
Ronin Posted February 13, 2011 Report Share Posted February 13, 2011 Noticed myself over the years that new barrels settle in at around 200 rounds. Velocity will rise gradually (in my experience) and then stabilise. Happened with all my current rifles in variety of calibres - not had a drop in velocity, without changing part of the load componant. Link to comment Share on other sites More sharing options...
brown dog Posted February 13, 2011 Report Share Posted February 13, 2011 Could be the temperature change between the time you last tested it and now? In addition to John's point, don't just think ambient temp; think charge temp. and/or Same distance from chrono? Same powder batch? Link to comment Share on other sites More sharing options...
Dan534 Posted February 13, 2011 Author Report Share Posted February 13, 2011 Powder - Same Batch of varget Temp - Yesterday 8.1oC, previous sessions 20oC! Summer last year. Varget is meant to be temperature stable, would it make that much difference? Accuracy on paper - wasn't quite as tight group just over half inch, could be my position on the day or a loose moderator! It Normally shoots about 0.3 of an inch. Chrono- approx 2 meters from muzzle Matt - Cards still worked at 666 meter target though on 5inch disk :-), 3 out of 4 shots hit 2/10th mil low though. Seems a big jump from 2855 to 2810 fps however. I'll try it again this week to make sure before fiddling. Link to comment Share on other sites More sharing options...
Ronin Posted February 13, 2011 Report Share Posted February 13, 2011 Your answer is the temp change Link to comment Share on other sites More sharing options...
duey Posted February 14, 2011 Report Share Posted February 14, 2011 That will be the temperature change as Mat has said Not unusual to get a 50fps velocity diferential between winter and summer temps Ian Link to comment Share on other sites More sharing options...
1967spud Posted February 14, 2011 Report Share Posted February 14, 2011 deffinate temp change as already advised Link to comment Share on other sites More sharing options...
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