ELR practice today

[Magnum_Willys]

Yes the friction is reduced so pressure and speed drops - acts like barrel just got bigger except no blowby. 
Getting up in round count so decided to play with barrel a bit.  Once I find max will see if it makes a difference.  They say it makes first shot more consistent, less cleaning, lower sd, perhaps greater speed. Will find out.   Certainly lowers pressure.

[jasnt]

Interesting.  Please report back how it goes

[Hilltop123]

Found a nice spot today. Lil windy but can drive to both target and bench at 960 yards.  338-378 was dialed in - lower left on target.  Was load developing Lapua with HBN.  Holey cripes!  Added 2 grains to get speed back up and looks like I need one or two more.  That stuff is slick.

HBN?   And what is this slickery witchcraft, you speak of?

[Jonathan_S]

Hex Boron Nitride, it's a micro coating in which some people tumble bullets. The coating supposedly decreases copper fouling among other things.

[Hilltop123]

Thanks!

Hex Boron Nitride, it's a micro coating in which some people tumble bullets. The coating supposedly decreases copper fouling among other things.

[Magnum_Willys]

Found a nice spot today. Lil windy but can drive to both target and bench at 960 yards.  338-378 was dialed in - lower left on target.  Was load developing Lapua with HBN.  Holey cripes!  Added 2 grains to get speed back up and looks like I need one or two more.  That stuff is slick.

HBN?   And what is this slickery witchcraft, you speak of?

Its like a fine white graphite.  Tumble bullets with a 1/4 tsp and some steel shot and it plates them with a slick coating.  Run two patches thru barrel soaked in it to pretreat ( one cup 99% alcohol to 1.5 tsp hbn)
It does dramatically reduce friction. Some love it some not worth it.   I’m in testing stage ( something new to fight the blues)   Costs $30 for lifetime supply. 

[Hilltop123]

Found a nice spot today. Lil windy but can drive to both target and bench at 960 yards.  338-378 was dialed in - lower left on target.  Was load developing Lapua with HBN.  Holey cripes!  Added 2 grains to get speed back up and looks like I need one or two more.  That stuff is slick.

HBN?   And what is this slickery witchcraft, you speak of?

Its like a fine white graphite.  Tumble bullets with a 1/4 tsp and some steel shot and it plates them with a slick coating.  Run two patches thru barrel soaked in it to pretreat ( one cup 99% alcohol to 1.5 tsp hbn)
It does dramatically reduce friction. Some love it some not worth it.   I’m in testing stage ( something new to fight the blues)   Costs $30 for lifetime supply. 

I'm curious to see your results.  Are you chrono checking your loads?

[Magnum_Willys]

Yep using LabRadar.   Was shooting 101.4 grains uncoated bullets at 2850.  Coating dropped speed by over 100 fps.   My first test was 100 gr to 103.3 gr but it only reached 2835 fps.   Shooting at 960 yds the hits confirmed speed drops.   Testing more tomorrow up to 105 if possible ( quickload suggestion)

[Magnum_Willys]

Practicing Social Distancing this morning at 965 Yards.

Cold Bore shot - only got one try with Uncles 338-378. 

Tried more of the HBN rounds today in 338 Lapua.  Interesting, saw some very low es.  But have to add a ton more powder to get speed back up and can't get the increase in velocity I was hoping for.   

Has potential at slower speeds but too much recoil at 2850+.   Scrapping HBN project on this rifle.     

[jasnt]

Nice shooting.  Too bad about the hbn.  I was hoping to hear it was the cats meow

[Magnum_Willys]

Got a Hornady FS die for 338-378 on Amazon sale for $17.   Neck was way small so used a hone to enlarge about 15 thou to 3.64.  Bumped shoulders back , and got less than .002 runout. Shot today with less than 2” verticle at 966.   Finally solved FS challenge with those bottlenecks.

Regarding hbn test on Lapua.  Cleaned barrel now won’t get speed back up. Wth??  Maybe time for that Proof barrel. 

[jasnt]

How many rounds down the tube?

[Magnum_Willys]

About 1000.   Shoots fair still - hard to tell nodes with speed variation but less than 3" group at 300.  All have been pushed pretty hard - Lapua brass 65k. 

This pic just off the neck is strange.  Carbon Ring ?  Tried power scrubbing, maybe need to try more.  Wouldn't think it would cause speed drop though. 

[jasnt]

Sounds to me like it’s about time for a new tube.

[b23]

I used to have a Wby MkV Accumark 338-378 and if I kept the loads somewhat mild-ish, it would shoot fairly decent, but no matter which powder or bullet I tried, as soon as I started to stand on the gas a little bit the goups would open up and the harder I tried to push it the worse they got.

I don't know what your 338-378 has on it for a barrel, but mine was just a standard factory gun and IMO the barrels they put on these big boys is way to small.  If I would have kept mine, it would have been rebarreled with either a 9 or 10 twist Hart or Krieger in a Sendero contour.  If I recall, the factory barrel on the Accumarks is only a #3 contour and it's fluted on top of them.  I think the standard MkV even uses a smaller contour.