Donation Donation
All Springer/NP/PCP Air Gun Discussion General > "Bob and Lloyds Workshop"
Comparing the Precision of Tin and Lead Slugs
subscriber:
--- Quote from: BigBird on September 28, 2021, 09:53:56 PM ---If you read up on lead bullets used in firearms there is a limit to how fast you can push them before you get leading.
--- End quote ---
You will get arguments about what that velocity limit is, but it is well over the speed of sound; when grease lubed bullets are used. Lead bullets are less common for rifle calibers because of this velocity limit. What will lead a handgun barrel badly is shooting undersized bullets, because that allows a lot of hot gas to blow by the bullet. Thus melting the bearing surface of the bullet and plating the bore with lead.
Airgun slugs are usually sized no larger than groove diameter, to reduce friction. In .177 and .22 calibers, slugs used are often 0.001" smaller than groove diameter. There is no risk of hot gas blowby melting the lead surface due to less than a perfect air seal. Pellet skirts start larger than groove diameter, but the force required to make them conform to the barrel is low, and subsequent skirt friction down the barrel is not significant.
With firearms, grease lubed bullets that contain tin and antimony to harden them, foul less than pure lead ones. With airguns, pure lead projectiles lead foul less than ones containing significant percentages of antimony. So, there is some commonality, but the leading problem and mechanism are not identical for airguns.
Once you have significant lead, plastic or copper fouling plated to the bore, it tends to increase friction with subsequent rounds. That heats up and tears of more material, so the condition can run away. This tends to open groups and raise pressures (in firearms).
The regime is preferred where each projectile scrubs out the little fouling the previous projectile laid down. This allows many shots without cleaning becoming imperative. There are many factors in establishing such a stable system, with bore finish being one of them. Using the "right lube" can also prevent fouling from adhering strongly to the barrel. Exposed bullet lube has to be managed, to prevent it from picking up and carrying abrasive down the barrel...
When it comes to plastic fouling of shotgun barrels, I wonder what cleaning regimen is used on those $2000 Browning Citori shotguns they rent out at skeet ranges? Or, are they smart enough to use ammo that has shot cups made from non or less fouling materials?
BigBird:
--- Quote from: BigBird on September 27, 2021, 08:59:39 PM ---
--- Quote from: Spacebus on September 27, 2021, 12:19:56 PM ---
--- Quote from: rkr on September 27, 2021, 12:02:01 PM ---What if we took a bore riding copper bullet and gave it two or three coatings with powder coat? That should increase the diameter by some 0.005-6" allowing it to seal on grooves of most barrels.
--- End quote ---
Is copper pipe suitable for casting copper bullets? I'm going to try and cast my own .45 ammo this winter. Wouldn't be a big deal to get a .452 (or whatever .005-6 undersize would be for my bore) mold and sizer and cast some undersized slugs. Someone else would have to do the powder coating, although I hope to be able to do that myself in the future. I'm also curious about trying my hand at casting tin, or maybe even a tin/lead mixture that won't fragment. I want to hunt game, but don't want to eat lead contaminated meat, or at least doing my part to not contaminate it further.
--- End quote ---
We always get deer sausage and often find bullet particles in them with our teeth. That lead me to believe making deer sausage was a lot easier for the butcher than I thought it was.
--- End quote ---
Case and point. Just eating some homemade chilli with deer meat and chomped on what I thought was a small bone. Copper-clad lead bullet fragment. Odd thing, all the deer we've got in the freezer are from either bow/arrows or pure lead airgun bullets. I always wondered how Boris the butcher turned around deer so fast.
MJP:
OT but, you dont butcher your own kills?
There is no velocity limit on where leading will start to happen, it's going to be more related to the surface finish than anything else. Rough bores gather more lead no matter what the velocity is.
Marko
BigBird:
--- Quote from: MJP on November 09, 2021, 04:09:49 AM ---OT but, you dont butcher your own kills?
There is no velocity limit on where leading will start to happen, it's going to be more related to the surface finish than anything else. Rough bores gather more lead no matter what the velocity is.
Marko
--- End quote ---
Our family used to get together after opening weekend for butchering (good times unless you are from PETA - wrong place/time) but they aren't around and it gets busy during the deer season.
I probably need to clean a couple airguns. I used to love cleaning a rifle but haven't done much on airguns except the D34.
Navigation
[0] Message Index
[*] Previous page
Go to full version