Do barrels slow down after awhile?

[Jerry Snyder]

I have a 26 inch Bartlein 6 Dasher 1 in 7 1/2 inch twist. I have about 1700 rounds down the tube. My typical load is 31.8 Varget, 5 off the lands.

This load used to produce 2880ish, but now shoots 2830. I did open a new jug of Varget, different lot number. Could this be the reason.? Thanks

 

[10XSHOOTER]

At 1700 rds down the tube. It might be getting a little big!!!
not as mush pressure to push the bullet as fast as it did before!

 

[Capt. Oblivious]

50fps might well just be the new lot of powder, load up a couple with 31.9 and 32gr and see what she does

 

[Willow]

I have a 26 inch Bartlein 6 Dasher 1 in 7 1/2 inch twist. I have about 1700 rounds down the tube. My typical load is 31.8 Varget, 5 off the lands.

This load used to produce 2880ish, but now shoots 2830. I did open a new jug of Varget, different lot number. Could this be the reason.? Thanks

Could very easily be the powder as ADI (who make Varget) tend to have more lot to lot variation these days after they tweaked the formula a few years ago after they made major renovations to their production facility. Barrels can slow down a bit towards the end of their life too, but I reckon your Dasher should be ok unless you machine gun it when you use it.

 

[distinguished]

As long as the accuracy is still there, just change the charge to match the new lot of powder.

 

[SKWERLZ]

Barrels can slow down after a lot of rounds.
At first a powder bump gets you back to speed for a while but eventually it get to be more trouble than it’s worth.

 

[Big Mc]

I have a 26 inch Bartlein 6 Dasher 1 in 7 1/2 inch twist. I have about 1700 rounds down the tube. My typical load is 31.8 Varget, 5 off the lands.

This load used to produce 2880ish, but now shoots 2830. I did open a new jug of Varget, different lot number. Could this be the reason.? Thanks

It,s a fact... We all do. Tommy Mc LOL

 

[Capt. Oblivious]

Barrels can slow down after a lot of rounds.
At first a powder bump gets you back to speed for a while but eventually it get to be more trouble than it’s worth.

Jip when you constantly need to adjust the load and seating to chase the lands its time to phone you GS to order a new barrel

 

[SSchnd]

Varget- I got a rifle from a buddy I shot using his components and he used 30.0 of HIS Varget but when I opened up MY Varget using the exact same brass I had to go to 31.0 Varget to get the same velocity.
Ladder test that new jug of powder and see what the target, brass and primers tell you.

 

[Bob3700]

As the round count increases down ur bbl, the throat is not the only portion of the bbl that wears. Take precision gauge pins and recorded the sizes that fit the breech n muzzle when it is new. Now 2000 rds later, those pins , that had a light drag fit when the bbl was new, drop right thru the entire length. The bbl internally wears all along its length.
So u can regain ur velocity but u will run into pressure issues sooner or later n the velocity is not coming back. Like the Capt. said, when u start adding powder to maintain ur velocity, get the new bbl on order.

 

[M-61]

Accuracy?

 

[JMayo]

Stop cleaning them to bare metal
Go in on lands
Tighter neck tension

These are the way i know to increase pressure.
But at that round count I'm thinking it is about done. I think 2100 is the most I've gotten in a bra. Idk dasher

 

[Superjet]

At 1700 rounds I’d spin up a new one and tune it to your new lot of powder.

 

[Jerry Snyder]

Jip when you constantly need to adjust the load and seating to chase the lands its time to phone you GS to order a new barrel

I just purchased a new replacement barrel for when this one is spent.

 

[Jerry Snyder]

Accuracy?

 

[Jerry Snyder]

1/4 to 1/2 groups.

 

[alf]

An example of one, but a different take on losing velocity....

When one of my Dasher barrels was gradually losing accuracy to the point I felt wasn't competitive any more, I pulled it after the last match. The barrel now had 2629 rounds down it. I read where guys will run a barrel till the velocity drops off before replacing, and since I had never chronoed a barrel in it's later life before, now was the perfect opportunity, as I still had a few loaded rounds left over.

I setup the bench, the chronograph, and ran the target out to the 600 yard line. Conditions were light, a slight breeze, but I didn't bother with wind flags. I shot two, 5 shot groups, writing down the speeds after each shot. Loads were with Varget and moly plated 105 Bergers. I had run the same load, regardless of temps or conditions, it's whole life, at 3075 fps. I was surprised that the velocities today were exactly the same as when it was new. The two groups average a half MOA, nice, but not competitive.

 

[Ahhnother8]

I did open a new jug of Varget, different lot number.

Highly likely the culprit, and the lot # is somewhat irrelevant. Sealed powder jugs get to us at about 50% relative humidity. Your previous jug likely had shed humidity over time and therefore burned faster. Your new, wetter/heavier, powder also likely takes fewer kernels to equal your preferred charge weight than the previous powder did. Everything matters...

 

[NZ_Fclass]

There's a few good nodes for Dasher. I have used 31.6 and 32.5. Try a higher one - and it's likely a powder burn rate issue. A lot of H4350 (AR2209) earlier this year was on the slow side too.

 

[TTE]

As long as the accuracy is still there, just change the charge to match the new lot of powder.

I agree with this ................. Oh ! and order a new barrel. You will need it sooner or later