Range Report Moly burnished barrel

[gvanhyning]

I'm shooting a 6.5x47L and after reading the 6.5x47L Accuracy thread thought I'd try the 130 grain Berger VLD's again with Varget. I did initial testing a couple of weeks ago and had what I thought was good results. The load I settled on was 37.5 grains of Varget, CCI BR4 primers and jumping the 130. Velocities weren't bad but not great at 2850 fps. One of the posts mentioned jamming .005 into the lands so I put together some rounds for another trip to the range. Prior to going back to the range I cleaned the barrel down to bare metal. The barrel is a 24" Rock Creek and is moly burnished at the factory. My barrel had 2200 shots and after the cleaning I burnished the bore with moly from Sentry Solutions. I got to the range, set up the chrono (CED Millennium 2) and fired 10 rounds to foul the barrel. Monitoring theses shots on the chronograph, the velocities were easily 100 fps faster. At the end of test shots the average velocity was 2959 and the best group was jumping .020". I was wondering if anyone has experienced a similar occurrence regarding increased muzzle velocity with moly. I understand there will likely be an increase in velocity but I had not expected 100 fps. Any thoughts?

 

[BOLTRIPPER]

Re: Moly burnished barrel

i break steel targets with Moly

 

[dar1246]

Re: Moly burnished barrel

Yes, I have increased vel. with moly.

 

[memyselfi]

Re: Moly burnished barrel

I had the opposite result with moly bullets.
223 69 grn SMK ( 20" barrel 1in7 ) non coated/ over 23.8 grains Ramshot Tac/ avg 2818 fps . Moly coated/ same charge/ avg 2778 fps. To get the same velocity and POI I bumped the moly charge to 24.2 grns.
Side note: I fired the non coated first when comparing velocities.

 

[gvanhyning]

Re: Moly burnished barrel

Shooting moly coated bullets is much different than shooting "naked" bullets down a moly burnished barrel. There is a general consensus that shooting moly coated bullets is not healthy for your barrel. Moly coated bullets tend to leave moly deposits in the throat which are fire burnished in and builds to a point that there is excessive buildup that is next to impossible to remove.

 

[Leaddog]

Re: Moly burnished barrel

Moly coat increases the diameter of the bullet ever so slightly and creates a tighter bullet to bore seal. Increased velocity is the result.

I am not a fan of moly for some of the reasons posted above.

 

[gvanhyning]

Re: Moly burnished barrel

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Leaddog</div><div class="ubbcode-body">Moly coat increases the diameter of the bullet ever so slightly and creates a tighter bullet to bore seal. Increased velocity is the result.

I am not a fan of moly for some of the reasons posted above. </div></div>

I don't shoot moly coated bullets, only burnish the bore. Rock Creek burnishes the bore of the barrel at the factory and I thought I would re-accomplish that at regular intervals.