250-51-FN (Bob’s Boat Tails)

The chamber may or may not require some work for the bullet to chamber easily…. Will stabilze in the MRod .25 cal 15.5″ twist rate, and fits the .25 cal MRod magazine…. Not sure about the Hatsan barrel, it will likely be stable if you don’t push it too fast, but it will fit the magazine…. Will work great in the .25 ACP barrel from TJ’s, which is 0.250″ cal x 0.243″ land with a 14″ twist…. Bob

I’d be in for a double cavity

I guess I should let Al answer, but I asked the same question and he told me that the minimum size Meplat for his HP conversions is 0.200″…. so this doesn’t qualify…. Perhaps if we raise enough stink, he would consider a smaller HP pin setup that could go down to about 0.156″ (5/32″) on the pin diameter and allow hollowpointing of smaller caliber bullets?…. Just a thought…. 

Bob

Nice to know, Al…. I think you might find that a popular option…. I would get one in every mold I am interested in that has a big enough Meplat…. What is the smallest pin diameter you can use?…. Can you go down to a 1/8″ pin and Meplat?…. I assume 5/32″ is no problem as that is the example I gave….

Bob

This was the most popular bullet in the Poll, so it looks like it will be the first one to progress to a Group Buy…. I, for one, would like to see the option of one cavity being available with a Lyman style removable HP pin with handle…. I will purchase a 2-cavity with one set up for such a hollowpoint…. I assume Al will link from here to the Group Buy thread when he sets it up….

Bob

I measured my Hatsan .25 cal barrel on the AT-44 Long this morning, as best I could without removing it from the gun…. Here is what I found….

Muzzle – pushed a .257 cal bullet in 1/2″ and pulled it back out…. 0.249″ land (or smaller)…. 0.255″ groove….
Breech – I chambered a .250 cal BBT by closing the bolt, and then pushed it back out…. no marks at all…. none…. and no resistance to chambering….
Twist – 17.5″

With these measurements being nearly identical to those for a LW barrel, and Hatsan supplying both…. I suspect they copied LW’s stated dimensions of 0.248″ land and 0.254″ groove with a 17.7″ twist…. Those measurements would be within my measurement tolerances….

If you are ordering either the 41 gr. or 51 gr. BBT from NOE for a Hatsan, I would suggest the 41 gr. in the larger size (0.255″/0.253″)…. If you want to try the 51 gr., you should be aware that since it has a recommended twist of 16″, if you push it too close to Mach 1, you may have a stability problem in the Hatsan barrels…. However, the Stability Factor works out to the recommended SF = 1.5 at 800 fps for the 51 gr in a 17.5″ twist…. so you will likely be fine at any velocity you could likely reach in a Hatsan, even a fully modded BT-65….

Bob

I’m taking a shot in the dark by chiming in on this thread because it appears it’s been at least 9 months since anyone else has posted to it. First of all, hello everyone. I am a NEWB to the world of PCP airguns. I recently purchased an Air Force Condor SS in .25 cal, and I love it. I grew up shooting guns, and of course my first “rifle” was a Daisy 880 pump BB/pellet combo. For a 10 year old kid, that gun was a dream! Well, now I’m 42, and this is the first air rifle I’ve owned since.

I’m a very methodical person. I’m always looking for a way to build a better mousetrap. Although highly impressed with the power and accuracy of my Condor, I know it can get better. After researching pellets for weeks, I discovered the inaccuracies over distance are due in part to the skirt of the pellet creating aerodynamic instability. The fix is a “boat tail” at the back of the pellet- which ironically you discovered WAYYYYYY before I did. So I’m curious, how much better the boat tail pellets perform over standard “skirted” pellets?

I’m curious if anyone has ever tried the boat tail pellets in an Air Force air rifle? The beauty of the Air Force is you can adjust the amount of air released upon squeezing the trigger, Maybe you can do it on other rifles are well. I don’t know. Like I said, I’m a noob to this world. But with as much as I’ve invested already, I’d love to find the best performing product for my set up. So any feedback you guys can give me would be greatly appreciated.

Oh yeah, I also noticed you have boat tail pellet molds in .250 and .253. I’m assuming that 3, thousandths of an inch was to compensate for a small amount of play when the .250 was inserted into a particular make and model of air rifle.

Thanks in advance for your time,
Scott

Bob, thanks for replying. How would I choke down the .253 pellet to .252? This is all very new to me. Do I need some sort of swage or press, or are the pellets ready to be fired straight out of the mold? I certainly don’t own the tools required to choke down a pellet by .001 inch. I wouldn’t even know where to start to accomplish that. My greatest fear is damaging the inside of the barrel or some of the other internal components on the gun by using a pellet that’s too tight. But I know that a proper pellet with a boat tail could increase grouping and accuracy dramatically. I don’t think shortening the barrel of the gun is an option. I know it can be done, but it would void the lifetime warranty. When you say “choked”, are you implying the barrel diameter is slightly smaller at the muzzle than it is at the receiver where the pellet is inserted? Sorry for all the questions. I just want to be confident in my investment before I pull the proverbial trigger.

Scott