Safety Tip for Loading With Coated Bullets
Coating bullets with a friction-reducing compound such as Molybdenum Disulfide (Moly) offers potential benefits, including reduced barrel heat, and being able to shoot longer strings of fire between bore cleanings. One of the effects of reduced friction can be the lessening of internal barrel pressures. This, in turn, means that coated bullets may run slower than naked bullets (with charges held equal).
To restore velocities, shooters running coated bullets are inclined to “bump up” the load — but you need to be cautious.
Be Careful When Increasing Loads for Coated Bullets
We caution shooters that when your start out with coated bullets in a “fresh barrel” you should NOT immediately raise the charge weight. It may take a couple dozen coated rounds before the anti-friction coating is distributed through the bore, and you really start to see the reduced pressures. Some guys will automatically add a grain or so to recommended “naked” bullet charge weights when they shoot coated bullets. That’s a risky undertaking.
We recommend that you use “naked” bullet loads for the first dozen coated rounds through a new barrel. Use a chronograph and monitor velocities. It may take up to 30 rounds before you see a reduction in velocity of 30-50 fps that indicates that your anti-friction coating is fully effective.
We have a friend who was recently testing moly-coated 6mm bullets in a 6-6.5×47. Moly had not been used in the barrel before. Our friend had added a grain to his “naked” bullet load, thinking that would compensate for the predicted lower pressures. What he found instead was that his loads were WAY too hot initially. It took 30+ moly-coated rounds through the bore before he saw his velocities drop — a sign that the pressure had lowered due to the moly. For the rounds fired before that point his pressures were too high, and he ended up tossing some expensive Lapua brass into the trash because the primer pockets had expanded excessively.
LESSON: Start low, even with coated bullets. Don’t increase your charge weights (over naked bullet loads) until you have clear evidence of lower pressure and reduced velocity.
Procedure After Barrel Cleaning
If you shoot Moly, and clean the barrel aggressively after a match, you may want to shoot a dozen coated “foulers” before starting your record string. Robert Whitley, who has used Moly in some of his rifles, tells us he liked to have 10-15 coated rounds through the bore before commencing record fire. In a “squeaky-clean” bore, you won’t get the full “benefits” of moly immediately.
To learn more about the properties of dry lubricants for bullets, read our Guide to Coating Bullets. This covers the three most popular bullet coatings: Molybdenum Disulfide (Moly), Tungsten Disulfide (WS2 or ‘Danzac’), and Hexagonal Boron Nitride (HBN). The article discusses the pros and cons of the different bullet coatings and offers step-by-step, illustrated instructions on how to coat your bullets using a tumbler.
Similar Posts:
- Safety Tip for Shooting Coated Bullets
- Safety Tip: When Using Coated Bullets, Adjust Loads with Caution
- Safety Tip: Adjust Loads Conservatively with Coated Bullets
- Reloading Tip for Coated Bullets — Adjust Loads Cautiously
- Reloading Advice: With Coated Bullets, Adjust Loads Cautiously
Tags: Boron Nitride, Bullet Coating, Danzac, HBM, Moly Bullets, Molybdenum, Reloading, WS2
When I changed from “conventionally” lubed bullets to polymer-coated ones in my old S&W Model 52 wadcutter wonder, without changing the propellant load, I learned an interesting lesson.
The gun fouled up so badly with un-burnt powder that it basically stopped in the middle of a 90 round match.
The coated bullets were starting to move forward VERY early, probably on ignition of the primer. This, of course greatly expanded the volume in which the minuscule amount of powder was burning AND decreased the starting pressure to the point that ignition could not be sustained.
Solution?
NOT more powder, but a slightly FASTER one AND a slightly deeper roll-crimp at the front of the case. Eventually off-loaded it and bought a 1911.
Shooting 12+ coated bullets to ‘season’ the barrel is the hard way to go. There is a better, quicker way I have been using for over 25 years with success.
Take a Parker Hale jag (J.Dewey) and wrap a cotton patch to get an extra tight bore fit and force it through a CLEAN bore first using only BC Gun Scrubber. Repeat, if it not TIGHT. Next, saturate the jag with a 30/70 solution of moly powder and Shooter’s Choice #7, swab the bore with it, and shoot a coated bullet. One is all it takes and the bore is ‘seasoned’ with moly.
CAUTION: This method is time critical, you have to quickly shake, coat, swab, and shoot without ANY delay.
1)Make sure the the solution is thoroughly shaken, not stirred.
2)Saturate the patch and immediately start swabbing back-and-forth 4-5 times. Don’t let the swab exit the muzzle or you will not be able to pull it back.
3)Clean out the chamber, then load and shoot the coated round, PRONTO!. That round should be within arms reach. The idea is not to let the solution ‘puddle’.
Like I said, I’ve been doing the above for years. And if I follow my directions to the letter, there will not be any problems.
Shooting 12+ coated bullets to ‘season’ the barrel is the hard way to go. There is a better, quicker way I have been using for over 25 years with success.
Take a Parker Hale jag (J.Dewey) and wrap a cotton patch to get an extra tight bore fit and force it through a CLEAN bore first using only BC Gun Scrubber. Repeat, if it’s not TIGHT. Next, saturate the jag with a 30/70 solution of moly powder and Shooter’s Choice #7, swab the bore with it, and shoot a coated bullet. One is all it takes and the bore is ‘seasoned’ with moly.
CAUTION: This method is time critical, you have to quickly shake, saturate, swab, and shoot without ANY delay.
1)Make sure the the solution is thoroughly shaken, not stirred.
2)Saturate the patch and immediately start swabbing back-and-forth 4-5 times. Don’t let the swab exit the muzzle or you will not be able to pull it back.
3)Clean out the chamber, then load and shoot the coated round, PRONTO!. That round should be within arms reach. The idea is not to let the solution ‘puddle’.
Like I said, I’ve been doing the above for years. And if I follow my directions to the letter, there will not be any problems.
Interesting process Kent. Thanks for sharing.
I have tried shooting with moly and have gone back to shooting without it.
It is the same with barrel tuners, the only improvement is in the shooter’s mind. A match grade barrel, action, and good stock cannot be improved upon.
I was captivated when you mentioned that coating bullets with a friction-reducing compound can reduce barrel heat. My friend wants to get their barrel coated. I should advise him to turn to a company that specializes in barrel coating.