CBI 25" Varmint 260 Rem Match-- Lack of Muzzle Velocity

[Robinhood]

RC, the reason for POA being different than POI is so when you shoot the middle of your target out you still have a precise aim point that is not a gaping hole .

[SageRat Shooter]

Ok guys... Made another trip out this weekend and managed to reach 2800 fps... As someone mentioned earlier in the thread, My accuracy node seems to be between 2650 and 2750 FPS (somewhat below max MV). Managed to narrow it down to the Vhit N560 and good old reliable H4350 as they both get me good groups and just over the 2700 fps mark. Jury is still out on the IMR 7828 load... Will have to revisit that one as I didn't get the one hole group with it this time.

Got a riddle for someone though.... When I hit 2800 fps my POI dropped 1.5 inches lower than my loads in the 2650-2750 fps range... I would think that they would have been an inch or so higher given the extra velocity. Any idea why it would be lower rather than higher? I even did it twice just to make sure I didn't "pull" it, but the second one did the same thing.

[LoneWolf]

When you pick up velocity your round shoots flatter. Therefore at short distances like 100yds it has a lower ARC and lower POI. Glad you found the results you were looking for!

[SageRat Shooter]

Thanks LW!!

Can't tell you how much help you've been (as well as others) in helping me through this build.... You guys have all been fantastic, I only wish I could return the favor some day!! :eagerness:

[yobuck]

Thanks LW!!

Can't tell you how much help you've been (as well as others) in helping me through this build.... You guys have all been fantastic, I only wish I could return the favor some day!! :eagerness:

Well for starters you could sell the barrel to the guy with the high bid. lol
Meanwhile, weve only gotten to 100 yds with this thing.
Will it be another issue if results don't match data at 1000, or heaven forbid a mile?

[SageRat Shooter]

Well for starters you could sell the barrel to the guy with the high bid. lol
Meanwhile, weve only gotten to 100 yds with this thing.
Will it be another issue if results don't match data at 1000, or heaven forbid a mile?

I'm still splitting hairs trying to get the most accuracy I can out of it before I try to stretch her legs out. Will it be another issue if I don't match data @ 1000? OF course it will!!! But I figure by then, it will be because I'm just not good enough to hit anything at that distance....

As you have probably already gathered "I'm a perfectionist" or as close to it as I can get. Once I've achieved that, then I have to live with the results no matter what they may be. Will I be disappointed if I don't get the results I'm hoping for? Sure... wouldn't everybody? A Mile probably won't happen as I don't have the velocity to get there using my FFP Scope. So it will have to be a max of 1400 yards or so.

[LoneWolf]

Just pay it forward! Help the next guy out with honest experience!

[darkker]

Every bullet is different. In my 243Win I tested both the 105 Hybrid and the 105AMAX. With the same charge the 105AMAX was around 80fps faster. There's no perfect science to what a bullet will do in a barrel.

Would bet that had more to do with the throat and the chamber than the bullet.
I agree that some unexpected things can happen, but when measuring with pressure equipment, that isn't what you see. Use one rifle, one load, same jump to lands, but swap bullets, and you won't see a difference.

[LoneWolf]

Would bet that had more to do with the throat and the chamber than the bullet.
I agree that some unexpected things can happen, but when measuring with pressure equipment, that isn't what you see. Use one rifle, one load, same jump to lands, but swap bullets, and you won't see a difference.

I would put my money on the fact that the 105AMAX has a much longer bearing surface than the 105 Hybrid. More surface contact means more friction which would contribute to more pressure as that's the only way you'd see more velocity from the same load. Maybe you can't see it on your test equipment, but something is happening there. Regardless there's a difference in the way different bullets react in a barrel. Otherwise everyone would use the same result....

[yobuck]

I'm still splitting hairs trying to get the most accuracy I can out of it before I try to stretch her legs out. Will it be another issue if I don't match data @ 1000? OF course it will!!! But I figure by then, it will be because I'm just not good enough to hit anything at that distance....

As you have probably already gathered "I'm a perfectionist" or as close to it as I can get. Once I've achieved that, then I have to live with the results no matter what they may be. Will I be disappointed if I don't get the results I'm hoping for? Sure... wouldn't everybody? A Mile probably won't happen as I don't have the velocity to get there using my FFP Scope. So it will have to be a max of 1400 yards or so.

Well apparently, I have more faith in you than you do as for your ability to hit things you shoot at. lol
I think much has to do with information overload with this stuff.
You've already decided your handicapped by your scope for example.
Just go shoot, and then figure out what needs fixing and why.

[SageRat Shooter]

Thanks for the advise YoBuck... And I appreciate you thinking I'm a better shot than I do. LOL!! I've never shot past 500 yards in my entire life (22-250 on the P-dog field), and have never hit anything past 450 yards. I can't have confidence in something I've never attempted or achieved... My entire build was centered around the 1000 yard mark (as I figured that to be a nice round long range number) and if I could hit a 10" plate at that distance, then that would be "good enough for the girls I go with" as my pop says... So, my scope isn't a handicap for what it was originally intended.

I will choose my load here soon and then do as you suggest.. "Go shoot and figure out what needs fixed from there".

Gotta say, you make it sound like "Shooting at 1000 yards is like a chip shot"... :whistle:

[yobuck]

Don't get the impression I'm saying its a chip shot, because it isn't.
And I'm also not saying that there aren't some very knowledgable people, some of whom are also very good shooters here on this site.
But what I am saying is that average Joe shooter, who can shoot 1" groups from a bench at 100 yds, can also do well at much longer distances.
On the days that you wont shoot well due to bad conditions, the better shooters will have problems also, but you wont always hear that.
As for a mile, we hear lots of talk about that today, but also realize that's about all it amounts to for the most part.
Take a look at the mid range trajectory height above ground of your cartridge, or any of them for that matter.

[SageRat Shooter]

http://rs345.pbsrc.com/albums/p385/SageRatShooter/Final%20load_zpsqssprxj1.jpg~c100?t=1499609486

Found the load this weekend guys... Thanks again for all of the advise. 43 gr. H4350 with the 143 ELDX (2750 FPS) may drop it back to 42.8 and mess with seating depths to keep this kind of group going as I did have some ejector marks on my brass @ 43 gr. We will see if the pressure is a little less using once fired brass (in my rifle).