Look man…I’m just sayin the dremel is a solid option. Could probably also flute my barrel with it too.
Now we're talking. Input!I’ve put about 2500 rounds of 175gr through a specific 20” 1:12 twist LW barrel.
My experience with it showed it did not group the best at 100m but actually tightened up at moderate distances, almost as if initially the bullet had gone to sleep.
Looking at some of your groups in an earlier post it seems you are doing the same thing by fighting that twist rate.
Especially out past 1000 yards with your bullet selection.
The one round I found to do really well was the 176gr A-TIP, the BC bump and design of the projectile lended well at 1000+ yards.
I do see what you’re trying to do and you’re definitely pushing the limits of your system!
I was wondering when you would chime in with that Q stock
This was the 20” setup I shot 8-9 months ago for a 3 week course.
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That's also an AT-X with a Bartlein 5R 1:10 twist barrel, is it not? Unless you retrograded it to the Walther barrel?
Thats a walther barrel I got from a guy who didn't need it anymore. I also have a 24" Bartlein 5R 1:10 twist barrel that I had spun up
Anyone know if there is there a 12 round magazine option for the AT-X / XC? I have a few of the earlier model double stack AXMC magazines which squeeze in 11 rounds which gets me close. I also tried using an AI AX AICS 10 round magazine (PN 6955) which can take an extension, but the bolt body scrapes against the magazine's single stack feed lips.
Ya I saw those. I'm using 6.5 CM and 25x47 Lapua. The OAL is too long in both of those I believe
Laughs in 14-round mag.
The fact that prs came up with 12+ round mags just to circumvent doing a mag change is comical... Seriously just load up a drum and just don't reload the whole match and it will probably take that 30lb 6gt to 35..... bush league
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I just got two of their AXMC/AXSR mag holders. What a great design and build...top quality, for sure. Easy to use, and they work perfectly
Congrats...welcome to the most exclusive club...LH AI Owners
Right. At the geiselle gas gun matches I use 40s for my ar and 33 stendos for my Glock.It's not just PRS. When I shoot AR tactical matches or certain divisions of USPSA I will use 40rd Magpul mags or big stick 2011 mags. It's just a competition. It's not combat.
I do well
#accuracythroughvolume
I have used these for general shooting. I'm not all that impressed with their performance.
I shot them out to 600 at my local range and 5 shot groups opened up past 400 yards compared to FGMM or TRU 168 grain cartridges.
Norma used to be cheaper than FGMM, which made them a good deal. The difference is a lot closer now. I'd rather pay a little more and be assured of better performance
Has anyone tried this ammo out of their AI’s?
Makes more sense for training and positional work spending less than a buck per round.
www.theamericanmarksman.com
Makes more sense for training and positional work spending less than a buck per round.
Bullets 1st .308 WIN 175 gr Sierra MatchKing HPBT - 400 ct.
www.theamericanmarksman.com
Transonic begins at 1350-1320fps depending on atmospherics. A kestrel will show clearly when transonic begins, and why you see (*) before each distance when looking at the Range Card.In fairness to HKSniper guy, AB does teach that the transonic window where percussion starts is a velocity range that equates to a couple hundred yards prior to the exact velocity of subsonic.
And every round will have a different range of distance. One round it could be 100 yards of distance. Another, 200 yards of distance. All depends on the velocity and BC of the round + atmospherics. It's physics: Ballistics are different in the Supersonic, Transonic and Subsonic ranges.
I'm a self proclaimed mag change expert. But I'd rather not do it during a PRS stage if I can help it
The transonic region is between Mach 0.8 and 1.2 but how it affects an object really depends on the specific aerodynamics of that object. At the most basic level "transonic" really means that you're in a region of speed where there may be some subsonic flow over your object and there may be some sonic (Mn=1.0) flow.
Conjecture time: understanding the weird aerodynamics that occur in this region really matters for aircraft or things trying to accelerate through the speed of sound. Since a rifle bullet is sledgehammered through the sound barrier in the barrel we really don't care about that but we do care about the deceleration side downrange. I remember reading that 168gn Sierras hit a wall at distance as when they went transonic the shockwaves would collapse and destabilize the bullet due to its boattail angle. Whether or not this is true got me thinking about deceleration through the sound barrier and I would say that first, rifle bullets are shaped very consistently so your transonic region will be a lot tighter than 0.8Mn to 1.2Mn. Second, the destabilizing effects will only be shown by either a localized subsonic flow or total collapse of the shockwave meaning it'll be closer to the slow end of the transonic region. Third, the bullet is supersonic until that happens and once shockwaves start collapsing the drag will increase fast and the bullet will quickly be subsonic and out of that region.
Having said all that I've never read any true ballistics books, this is just me guessing at some things based on my understanding from being around some aerospace engineers in college and trying to make the transonic stuff a little easier to understand. Hopefully I labeled my guessing areas well enough and have given sufficient disclaimers to say if you actually listen to me that's on you.
Conjecture time: understanding the weird aerodynamics that occur in this region really matters for aircraft or things trying to accelerate through the speed of sound. Since a rifle bullet is sledgehammered through the sound barrier in the barrel we really don't care about that but we do care about the deceleration side downrange. I remember reading that 168gn Sierras hit a wall at distance as when they went transonic the shockwaves would collapse and destabilize the bullet due to its boattail angle. Whether or not this is true got me thinking about deceleration through the sound barrier and I would say that first, rifle bullets are shaped very consistently so your transonic region will be a lot tighter than 0.8Mn to 1.2Mn. Second, the destabilizing effects will only be shown by either a localized subsonic flow or total collapse of the shockwave meaning it'll be closer to the slow end of the transonic region. Third, the bullet is supersonic until that happens and once shockwaves start collapsing the drag will increase fast and the bullet will quickly be subsonic and out of that region.
Having said all that I've never read any true ballistics books, this is just me guessing at some things based on my understanding from being around some aerospace engineers in college and trying to make the transonic stuff a little easier to understand. Hopefully I labeled my guessing areas well enough and have given sufficient disclaimers to say if you actually listen to me that's on you.
I couldn't agree more. But I'm also not experienced enough to know how to build a Custom Drag Model besides sitting there and shooting rounds at a target within the transonic window. So for those who don't know -- and myself now researching how best to build CDMs -- I'm leaving the info below here. So it sparks an interesting debate: use a round that is supersonic at 1000 yards but doesn't group as tight, or use a round that groups much tighter, but needs a CDM to hit 1000 yards on target consistently?
* * *
Custom Drag Models (CDMs) are used to model the flight path of bullets, and are particularly important for accurately predicting trajectories beyond the transonic range. The transonic range is when a bullet slows below Mach 1.2, or around 1340 feet per second (fps).
Here's some more information about CDMs and the transonic range:
CDM accuracy
CDMs can provide highly accurate predictions, with one example showing a match within +/- 9 inches for a bullet traveling up to 1323 yards.
CDM generation
CDMs are generated using Doppler Radar to directly measure a bullet's drag profile.
CDM availability
CDMs are available for all bullets in the Applied Ballistics software ecosystem.
CDM benefits
CDMs eliminate the variation between a bullet's actual drag and the standard model being used.
Transonic range challenges
The transonic range is difficult to predict because of the mismatch between the standard G1/G7 drag curves and the bullet's actual CDM.
Transonic range effects
The transonic range can cause bullets to yaw and destabilize. Short, flat base bullets are less affected by the transonic range than
long, thin bullets.
Regarding the factory AI AT 308 barrels with the UK proof markings, do they speed up with use?
I got 2,550 with my 24” and 175 FGMM for the first ten rounds fired.
-Stan
I got 2,550 with my 24” and 175 FGMM for the first ten rounds fired.
-Stan
What are your thoughts on 4DOF since it uses muzzle velocity as a known parameter? Sounds like you might like that better than the AB method...
You could just shoot 6.5 and use Strelok like the smart people do
Instead of pondering Sonics and other nonsensical bs
Instead of pondering Sonics and other nonsensical bs
Depends on the round used, the friction of the barrel, and the thermodynamic characteristics of that barrel. No one can given an answer. Just start writing down speeds over time. Ultimately, there should be a change as a new barrel "breaks in and settles down" no diferent than the horsepower of a car when first built versus the power of that car after the engine is broken in. Don't think anyone is really going to give you a better answer. Give it a couple hundred rounds and see what happens.
AI doesn’t just make you a great shooter,
It also makes you a pretentious Ballistic professor!
C’mon we all know what happens when you own one.
It also makes you a pretentious Ballistic professor!
C’mon we all know what happens when you own one.
This is supposed to be an AI pic thread not an AB ballistics theory thread...
so back on topic please.
so back on topic please.
My bad.Bro, we're trying to nerd out over here on some super serious high brow theoretical ballistic shit; super important high end stuff! ....and you're butting in with some mouth-breathing day 1 shit like, "Do barrels speed up?".
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I left out the word when.
As such, I shall new rephrase:
“When (as in round count) do the AI UK barrels in 308 begin to speed up?”
That should do it.
-Stan
I’d say 100-200
Seen some barrels as quick as 80
24 or 26" barrel? Hella gorgeous AW. Loving the Parker Hale bipod on it... I ought to grab one some day. What's the scope? I don't recognize it.
Mohawks are an option too. I chose the latter. I'll make this photo a one time thing.
Burt’s trying to pass off another one of his transvestite AI’s again…
Fess up, Burt, you were wearing your yellow sun dress with the red pumps when you took that picture…
