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I am running some numbers and reading more that I want to know.
Of the 3 rounds in your opinion how well does the 20 pract shoot at 500 yards? Can it be as reliable at 500 yards as the other two rounds?
Is a 40 grain 20P is 4000 fps a realistic velocity?
With my current 22-250 I get about 30" of drift at 500y with a 10 mph wind, the 20P is showing a 24" drift with the same conditions.
I shoot a 20 PT w/12 twist....40 V max moly @ 3900 fps......26 gr charge
500 yds...its just getting warmed up at 500.......
seriously I have killed p/dogs with mine at 740 yds...
As in any p/dog rig...once dialed in the dogs fall......
Wanna shoot a 90 gr ? Do it with a 6mm.....
The 22-250 does not interest me...
Thanks, few questions....
Whats your group size at 100 and 200y?
With a 10mph full value wind at 200-400y how is the round?
Other than swapping bushings on the die, do you neck turn or do any other mods to the case?
Not to conflict what anyone else has said, or seen, but my results withthe 20 Practical are a little different.
First of all, I love my 20 Practical- it is built off of a Savage PTA with a 26" Criterion 1:11 barrel. It is by far the most accurate gun I own. I shoot the 39gr SBKs in Win brass over 23.1gr of H4198 with CCI 450s for 3860fps.
If you look around here and on Saubier.com you will find many targets I have posted that show that this combo is good for 1 hole groups at 100, 1/4" groups at 200 (1/2" at 200 all day long, 1/4" when I'm more lucky than good) and 1.25" groups at 400 yards.
I took this rifle to WY this last summer and was amazed at how well it did in the wind, very, very accurate and murder on prairie dogs out to about 400 yards.
And that's the kicker- out to 400 yards the round is a laser, after that, in my opinion it starts to fall on it's face pretty quick. Some may argue, some are undoubtably better shots, better at reading the wind etc than I am.
To go beyond 400-450 yards I don't think any of the rounds listed are optimal. Can it be done? Sure, but the 20 will hang with either of the others out to that range and neither of the others will walk away from it after that. To go beyond 400-450 is to step up to a 243 etc in my opinon.
+1 to Mattri
I have a 25-06 that I use for heavier winds or further distances. It's a great gun but more expensive to shoot just for groundhogs that lay in the fields after the shot.
Do you have any problems with pressure at the higher velocities?
The gun will be setup with a Nikon MD scope, if the round is still stable at 400y+ its a plausable hit. Does the round start losing spin stability at that distance or is it wind drift and loss of velocity?
In my experience/opinion its a little of both. Again, the 20 is an absolute laser out to around 400 but every round has an operating envelope and when you get outside of that you're going to have problems. There is only so fast that you can reasonably send the 20 cal pill downrange and it will bleed velocity pretty quick. From what I've seen 400 yards +/- is about the range that you can expect sub moa accuracy out of this round under field conditions. On paper targets off of a steady bench at known distances is different. But for killing, will it hit farther out? Of course. But consistently, effectively? Not to a level that I'm ok with. Re pressure- my gun shoots 23.1gr of H4198 very well. That doesn't mean that yours will and it should be noted that this is about .5gr above max in a comparable 223 load. Whenever you start pushing the upper regions of case capacity, charge weight, pressure curves etc you're going get to a point where you have little wobbles in your results. If I push any harder than the above load I can get phenomenal accuracy with no pressure signs, sometimes. Other times its a stick bolt, a spike on the chrono or an unexplained flyer. When you push velocity thats what you get. Again, and I really can't overstate this- I am by no means an expert on any of this. These are just the things I've seen with my gun.
The rate of spin on a bullet decays very, very little as is goes downrange. Because of that, stability actually increases as velocity bleeds off. The problem is that as the velocity bleeds off, and the .204cal pills are not very efficient so they bleed velocity quickly, wind drift increases at the same rate. You can send a bullet fast enough from a .20 Tac that wind becomes almost negligible out to 300yds or so, but after that it starts to becomes a huge factor as the velocity decay catches up. For a 40gn VMax with a MV of 3900fps, wind drift is 7.7" at 300 yds. At 400 it's 14.4", by 500 24". A 32gn @ 4100fps drifts 10" @ 300 and over 30" by 500.Quote:
Originally Posted by jon8777
And those numbers are based on a wind blowing at a constant speed in one direction.
Yes, SWAG and good luck help with 400+ shots
Yep, so any variability only makes it that much more difficult to deal with.Quote:
Originally Posted by mattri