Question for Big Bore ammo experts

[Butcher45]

I must try this EPP/UG 150+ Grain Bullet that Emulates a Standard Round Ball in my Tuned 909S and see what it will shoot like with a 150+ Grain Bullet in place of a 230 Grain.
                                                                                    Jetman

It will shoot like a laser in comparison.......when zero'd at 50, you'll likely have less than a foot of drop@100yards, compared to the 15inches or so of drop you'd get with the 230grainer.

The difference may not help much, or at all with heart/lung shots on large animals like deer, but for smaller critters with tiny kill zones, I have more confidence in the flatter-shooting boolit.  With my style of hunting, and the quarry I pursue, I stay within my rifles point blank range by choice (and usually by circumstance as well), so holdover need never cross my mind.  I choose the precision, and bit of extra range I get from a 154grainer for stuff smaller than deer.

The EPP/UG has been catching on as of late......very good consistency with the accuracy reports from SamYang owners (often shooting un-sized boolits, which is what I shoot out of mine).  Under an inch c-to-c groups at 50 yards seems typical, with some trophy groups closer to 1/2 inch. 

[jetmangd]

Thanks Butcher & Rsterne.
             
 I understand much more now on Conical Bullets , Etc. Butcher, Thank you for the Detailed explanation. I always understand in clarity from the way that you word things. Like I stated Prior, You are a Full Encyclopedia of Big Bore Air Guns and Related Information and then being able to write it down in a Clear and Easy way for Air Gunners like me to Absorb. Bob, Now I do need
to Clarify something however. I thought that a longer Conical Bullet was More Stable than a Shorter one and that the Spin from the Rifling also Stabilized it. What do I have Backwards ? A conical can be made as long (and therefore as heavy) as can be stabilized by the rifling. Early conicals were very short because they were used in round ball rifling patterns. Conicals can also be made in different lengths to allow for a wide variety of game hunting. But, a Conical can only be made so short before it becomes unstable. The largest Conical Bullet that I have shot from my Tuned 909S is A 230 Grain HP from Bob Vogel # 456-230-K ( See Picture ). I try to choose a Conical Bullet that loads easily in my Rifle and a weight of Conical Bullet that is appropriate to the game I am hunting.

                                                                      Jetman

[rsterne]

I'm not familiar with "Conical" bullets.... All I know is that if a bullet of "X" length is stabilized in a given rifling twist.... that a shorter bullet will also be stable.... ie it will not tumble end over end.... If the bullet is short enough, it can be "overstabilized".... While in theory this not a problem with a PERFECT bullet.... if there is any imperfection.... out of round, CG not in the center, loaded crooked, etc.etc..... then spinning it too fast can cause it to wobble and open up the group size.... Perhaps that is what you are experiencing?.... It might be something as simple as the short bullets not loading straight....

If you can give me an example of the longest, heaviest bullet that is stable in your gun.... and the rifling twist and velocity.... I can crunch the numbers.... Likewise, if you can tell me where the lower limit is (the shortest, lightest bullet that is stable).... I can do the same.... The military generally aim for a stability factor of 1.5 to 2.5 (anything under 1.0 is unstable).... Bench rest shooters aim for 1.3.... Anything up to about 3.5 or 4.0 is usually not detrimental unless the bullet is of poor quality (off center, crooked, or out of balance)....

Here is an example of what information is available on the Internet.... This is for a Lee 405 gr. in .457 cal # 90374 in a 1 in 26" twist barrel.... I took the dimensions from their photo on the website so they may not be perfect.... but good enough to do the calculations.... The stability graph is from a website in Scotland....    http://www.border-barrels.com/barrel_twist.htm



You fill in the dimensions in the calculator and it produces the graph.... This is the ONLY website / calculator I have found that addresses the subsonic and transonic regions.... Note how the stability drops as the bullet falls through the sound barrier.... I don't know if this will help you or not.... Hope so!....

Bob

[jetmangd]

Rsterne,
          
Bob, Thanks for the Information, However Butcher45 and Nomadic Pirate were Talking about a 270 Grain Conical And a .50
Caliber Dragon Slayer. I jumped in because of a few things I read and it did not add up for me. So i jumped in and learnt a
thing or two.

I have no problem with any of the Conical Bullets I shoot in any of My Rifles.My Leroy Power Tuned Sam Yang 909S shoots A
 230 Grain Hollow Point Conical ( Bob Vogel Bullets/ MHP ) @ 755 Plus FPS for just over 300+FPE. I have also shot A 250 Grain    Hollow Point and My 909S,It is Very Accurate and it is Very Healthy in the Power Department. I was saying to Butcher45 that I have to Try shooting this EPP/UG 150+ Grain Bullet that Emulates a Standard Round Ball in my Tuned 909S and see what it will shoot like with a 150+ Grain Bullet in place of a 230 Grain HP. I also shoot A 433 Grain Conical HP Bullet from my .58 Caliber Haley Boomer Carbine and it shoots Just Awesome. I have been shooting the 182 Grain Soft Lead Round Ball and a few Soft Lead Conical Bullets from Bob Vogle ( A 200 Grain HP & 240 Grain HP from my New DAQ .50 Caliber Outlaw Bandit and so far the 182 Grain Soft Lead Round Balls are 80% Hole in Hole @ 30-50 Yards and I can cover up my 3 Shot Group with a Quarter , And I am covering up 1/2" Diameter Holes from my .495 Lead.

Bob,
That is real nice of you to offer Tech Help. That stuff is a bit Complicated when I here Crunch Numbers. With my 909S I am shooting a 230 Grain HP @ 755 + FPS for just over 300 FPE, However this gun is shooting Great. When I get the .50 DAQ Power Tuned I will ask for your help then if that is all right. You seem to have a computer mind ( A Complement )when I comes to Air Rifle Charts Etc. I understand some of the stuff, But Wow, Some of it sounds like Physics or Something. Thats real cool you can
crunch numbers like that. It is another learning curve I need to Master.


                                                                          Jetman
 
 

[longrifle]

Jetman,  Do I understand that your  Quackenbush .50 Cal. Shoots 182 Grain balls at 800 FPS?  And your accuracy is best with the balls? What is the fill pressure and how many full power shots do you get with it? Have you killed any deer with it as it is?  I seen one of your post that you may have it tuned. How much improvement do you expect from that? When you have it tuned will you let us know what improvement you see? Sorry for all of the questions but I plan on getting one and want a lil insight. Thanks Longrifle

[grizzlyadams]

the longer a bullet is the faster it needs to be spun to stabilize. higher velocity can be used to compensate but only to a certain extent. that is why sporter 223 barrels had a 1-12 or 1-14 twist for 40-50gr bullets and military 5.56 have as fast as 1-8 to shoot 60-80 gr bullets in the same cal