how much has your 6BRX or dasher slowed down

[comagutsa]

my 6BRX shot like a dream till it hit approx 1100 rounds , when it had 200-250 rounds I finished my.load testing and had 3000fps with a ES of 5 and a SD of 2.4 with 32.4gr of varget/2208 and 105gr hybrids and cci450s. tested on magneto speed
I followed lands as they wore to keep it .008 off the lands..
then after 1100 rounds it just wasn't right and ment to Check load but was to busy and weather wasn't kind to me..
I pumped up load to 32.7gr which was better but still not great, and made up some rounds to test up to 32.9gr
i received my Labradar the other day and took it to a 500m fly match and shot my 32.7gr loads ..
I was shocked the speeds had dropped so much. now only 2963fps ES 14 and SD of 4.4 and it had 2 to 3 inch of vertical..
on 3rd round I took out 7 of my 32.9gr loads and shot them. and got 2979fps with ES of 4 and SD of 1.6 and vertical went to an inch which was great ,like old times . I still want to test 33.1gr but I just can't get over how much the speed dropped off
original 32.4gr load must of been 2930fps or something down from 3000fps .. is that normal for speed drop off that much

on another note the same magneto speed I did my 1st load with, I tested at same time with the labradar and MS was the same or 1 or 2 fps slower than the LR over 8 shots

 

[Judd]

My theory is your freebore has increased (via you chased your lands) and you didn’t increase your powder charge. Therefore, you lost FPS. If you look at the powder charges of the guys running the longer freebores (.135 - .155) they aren’t getting the speed without increasing their powder charges. The guys running .104 get more speed with lower powder charges...for example, I’m shooting the .104 freebore with 32.6 Varget and running just over 3k...it takes closer to 34 with those longer freebores to get that kind of speed.

 

[Carl Ross]

Over 1800 rounds I've lost ~ 50 fps with essentially a constant load, although I have not chased the lands. Lands have moved ~ .035", so that is not insignificant. 110 SMK and 31.7 gr Varget, 2870 to 2820 give or take, it probably had 50 fps more in it initially where I'd still be comfortable with the pressure.

 

[comagutsa]

Yeah my FB is .110 and i have moved with the lands about .025 or so in that time. Least now i have a decent crony now and can keep a track of it and keep it in its sweet spot ..
In the short time i have had the LR i don't how lived without it haha

 

[KenOath]

Yeah my FB is .110 and i have moved with the lands about .025 or so in that time. Least now i have a decent crony now and can keep a track of it and keep it in its sweet spot ..
In the short time i have had the LR i don't how lived without it haha

Get yourself a BRA... 450rnds down tube and .002” throat wear. Same speed less powder

 

[comagutsa]

Get yourself a BRA... 450rnds down tube and .002” throat wear. Same speed less powder

haha you idiot you know I have a barrel made ..still waiting for the cops to approve 2nd barrel ...not happy
can't wait to try it

 

[BradY]

You lose fps faster with the bigger cals. Wondering if there is a link between powder burnt and bore dimension changing.

 

[KenOath]

haha you idiot you know I have a barrel made ..still waiting for the cops to approve 2nd barrel ...not happy
can't wait to try it

..Ill have burnt my first barrel out before you get yours run in!!!