Very light pellets at very high speed?
- Thread starter MrP
- Start date
I did not size them down. The slugs drop from the mold with .2555"-.2560” diameter at the driving bands.
It's a 25-20 barrel, .249" bore, .2555" groove diameter. It also shoots 34gr JSB .25 pellets fairly well as they have a 0.249" diameter head and a 0.259" diameter skirt.
Upvote 0
Tin casted lead 48gr comes in 33gr, hard to cast them, specialy fill them at the top. Accuracy is very bad at all speeds, price...
Upvote 0
elvis ammo on youtube did some powder burner tin bullets, I didn't follow closely but I remember he had to buy a new pot because the tin ate the steel of his pot. Check him out for more details and if I am mistaken the true details.
Upvote 0
Sorry this confused me, I know it’s old but. The fast the bullet travels don’t the fpe increase?
Upvote 0
The longer a bullet is in a barrel the more time the energy of the air has to work on it. So a very light projectile zips out of the barrel so quickly that the force is not applied for a long enough time to add a whole heck of a lot of energy.
Upvote 0
FPE development comes from force x distance, it’s not force x time.
Force is (pressure x bore_area).
Maximum distance available is barrel length.
Though actual distance and pressure is related to how quickly and how long the valve stays open.
For a valve that opens for only a short time period, the lower mass projectile will have higher FPE, since it travels a longer distance while under full pressure.
For a valve that opens fast, with full ports, and stays open, the heavier projectile will have a higher FPE because the proportion of air mass to projectile mass is lower.
Upvote 0
That’s what I was thinking, I know the length of barrel affect velocity, which intern affects foot pounds of energy. But that one confused me! Here’s another good question. At least it’s a good one to me. If we have airguns that push a cal 230 grain slug up to 900fps, why are there no 22, 25cal on the market that can push a 30-80grain slug up to velocities of 1300-1600 fps. Other than the whole instability thing. I have 25 cal pcp that hits 1190fps with 19.95grain h&n barracuda green lead free. That’s the best number I’ve ever gotten typically that just one shot in a string the rest 1160-1165. I don’t see a stability issue. And get quarter size groups at 30-40 yards and half dollar at 75-100yards with a couple flyers here and there. FX M3 in 25cal max power.
Upvote 0
Very well explained, I was just trying to keep it simple. So you are saying it’s not correct to say that the longer you apply a force to an object the more you’re able to alter its KE?
Upvote 0
the applied force doesnt directly = the objects energy .. its mass x velocity ..doesnt matter how it got that velocity
Upvote 0
I did a similar experiment years ago with a powder burner and the lighter projectiles were moving through the barrel so fast that they couldn't obtain the needed twist to stabilize in flight. They were fouling in the lands and grooves and a shotgun pattern would have been an improvement. I am by no means an expert but I do learn from my mistakes. So in the name of experimentation by all means give it a go and let us know how it turns out. Lots of things look great on paper or in theory but just don't pan out when applied to real life.
Upvote 0
Sometimes others just like typing what they've heard.well that is one way to go… sometimes it makes sense to learn from the wisdom of others
Upvote 0
It seems like in the airgun world that every gun is different, I have 3 impacts in 22cal. I can put the same barrel in all 3, and shoot the same ammo out of the same tin, and all 3 will perform in their own way. Best way to know if a lead free pellet will shoot well at higher speed, is to get a tin of them and go see. My guess... you'll have a real hard time even getting it on paper, but i could be wrong.
Upvote 0
Who all here had their 22 cal rifles shooting lights out with MRD's at speeds between 750-880, and then went to chasing the 970 fps unicorn when all the talking heads went to jumping on that bandwagon? I'm guilty.. eventually i went back to what worked for my gun... 970 works well as long as you have very little crosswind or worse tailwind. ( in my experience)
Upvote 0
If you ever get tuned to 970 with 25.39's and pick up a magazine loaded with 18's accidentally, it will be sending them supersonic, and they are not predictable in any way . All over the place. I did this once and it took me a second to figure out what i had done.
Upvote 0
That’s not what I said. A projectile will indeed gain FPE the longer (time) that you apply force, as long as it is free to move. However, if it does not accelerate very far (distance) down the barrel under pressure, it won’t gain much FPE.
Last edited:
Upvote 0
I have a hatsan blitz in 25 I shoot H&N barracuda green lead free out of it. They are 19.91 grain. To be honest it shoots those more accurately than most other lead ammo. I take starlings and crows at 75-100 yards. With few misses. As soon as I can find a good mold fairly cheap in .495 I plan on trying to make my own out of lead free solder of various types to see what works best. I figured instead of trying to mix my own alloy I can just choose from the ones that already exist as lead free solder.
Upvote 0
Not really, only if you can incrementally increase the force. Granted barrel length with increase fps in turn increases fpe. But only to the extent of the amount of inertia created by said force or the amount of energy that that force produces. At some point it will reach a point that the energy and the amount of force it creates is equal and can no longer accelerate any faster than what it’s already traveling. No scientist but I think it has something to do with conservation of energy.
Upvote 0