New Rifle what break in?

[sandwarrior]

Schneider has some interesting thoughts about liquid in the bore. Liquids generally don't compress. He argues that pressure (highly localized) is created between the bullet and the bore and that minor dimpling can occur to the barrel. I don't know..... Interesting.

This is a little more akin to what we see in the aviation world. Oil that would move from between to two surfaces at a few hundred feet a second (1000-5000 rpm piston engines) has no where to go in a 30,000-40,000 rpm engine like the turbine engines we use in aviation.

Therefore, we move a lot of it through, and give it a place to go. A barrel does not give it a place to go. I suggest a clean, not oily barrel to fire through.

 

[BoilerUP]

This is a little more akin to what we see in the aviation world. Oil that would move from between to two surfaces at a few hundred feet a second (1000-5000 rpm piston engines) has no where to go in a 30,000-40,000 rpm engine like the turbine engines we use in aviation.

Therefore, we move a lot of it through, and give it a place to go. A barrel does not give it a place to go. I suggest a clean, not oily barrel to fire through.

So yer saying I can lubricate my barrel with BP2380...right?

 

[gstaylorg]

To those that believe a thin layer of oil in the bore is a good thing, try compressing a liquid. They don't compress easily. That is why excess oil in the bore can cause pressure spikes. In addition, it's gone after pretty much one shot, so what good is it really doing? Having a layer of lubricant/protectant from one to just a few molecules thick will do everything that is needed with regard to lubrication and/or protecting the metal during storage, without the likelihood of pressure spikes. That is pretty much exactly what you will have if you run two or three dry patches through the bore AFTER the oil patch.

 

[Blackbrush]

I've read about guys using dry lube like graphite for first shot on a squeaky clean bores. 6mmBR is also a good resource for this kind of thing.

 

[sandwarrior]

So yer saying I can lubricate my barrel with BP2380...right?

I think the stuff works a lot better in engines than bores, but yeah....it'll work

I've read about guys using dry lube like graphite for first shot on a squeaky clean bores. 6mmBR is also a good resource for this kind of thing.

Most of the graphite I've seen used is pretty much a light dusting. I sure wouldn't go slogging in some white graphite grease Again, trying to compress the uncompressible will do bad things for pressure and your barrel.

 

[Greg Langelius *]

I don't think there's as large a disagreement here about oil in a clean barrel as might be. IMHO, a light coat means I dry patch before firing, but don't scrupulously attempt to get it all out, as with a flush with solvent or alcohol to remove any/all traces of oil.

As for .311 bullets in a .308 bore, that's not such a cut and dried nono either. That happens every day with 7.62x39's all over the world, and especially with American made barrels chambered for this cartridge, which are frequently fired with foreign (.311-ish) ammo in their .308 bores. Swapping bullet diameters between 9mm (.355), .38 (.357), and .35 (.358) caliber bores is another instance that's actually a lot more common than many believe. Palma, etc., shooters play games with bore diameters and bullet diameters as well.

The oil may be incompressible, but bullets are, and barrels are also elastic.

At full chamber pressure the barrel does expand and the bullet does foreshorten and expand to accommodate that expansion. That's simply an attribute of the obturation process. Trust me, you slam a bullet with 50,000-70,000 PSI inside a force-fit bore, and dimensions are gonna vary all the way down the bore in direct relation to the pressure curve. All that an effective lube is going to accomplish is to reduce friction, decrease bullet diameter, which in turn reduces pressure. Less pressure for a given powder charge means, pretty much always, less velocity. That's what drives max powder charge limitations, and why lubes like Moly add complexity (and perhaps confusion) to these relationships. This is also why some shorter barrels shoot faster than some longer ones; the bullet/bore fit is also a key factor in a specific barrel's ability at achieving its actual velocity.

Some subsonics shooters will even wet down their bores with water and achieve (some) diminution in acoustic pressures without actually employing a suppressor. I wouldn't, but the phenomenon has been observed and reported on this site.

Greg