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Your zero angle should stay the same, but you do need to update the environmental data for wherever you go. Altitude/Barometric pressure, temperature, humidity, etc.. all need to be updated. 4DoF will figure out the rest for down-range solutions.

The X's are about .040 longer, ballpark of 1.2" overall. More copper, more volume for the same weight, has to go somewhere.

We've done small tests with tens of different combinations but the one with the most data points was a 140gr ELD-M in 6.5 Creedmoor that I took from .015 jammed out to .050-.060ish jump every .015". The best groups were in the .020-.035" jump range but the worst and best groups were still...

The TLDR of primers is most of the time if it ignites the powder column it's doing what it's going to do. BUT..... you can mismatch the volume and burn rate of powder with too strong or weak of a primer and run into issues. Personally I'd generally stop using a SR primer somewhere around x47...

I've seen dinged extractors from hitting a sharp corner on a hard steel gauge. Ejectors can make it hard to snap the gauge under the extractor then feed it into the chamber. If you're a half step away from being asleep a guy could falsely head space on the extractor because the gauge rim...

Tight headspace is a functional issue. If they chamber and you're OK with a little resistance, you shouldn't have any issues other than the resistance. You should also have a window between GO and NOGO... So you could screw it down on a NOGO, mark a sharpie line on the nut and barrel, then do...

Any markings on the projectile itself? Sharpie the shoulder on the brass and the bullet to see what's contacting.

Didn't read through the thread but I tested my PRS gas gun with AGB through the functional range of gas adjustment and yes overgassing increases the occurrence and severity of errant shots. Also, however, muzzle devices-- as simple as a 6.5mm and .30 cal version of the same brake can cause...

No I didn't, but IMO that's slapping another bandaid on the wound. Better than nothing but maybe a guy should use stitches. Swapping to any flavor of CM or stainless steel immediately increases the rigidity 3x. If you had a stainless Seekins style upper I think you'd be in business. If you...

My experience with the Seekins IRMT3 and my 24" 6mm ARC barrel was .2-.3 mil total shift between shooting off a bag on a prop/barricade to a loaded bipod. Moving the bipod along the ARCA rail under the handguard also caused a slight elevation shift. Resting the bipod on grossly uneven surfaces...

Hill People Gear. I have a Junction but it's a little small and could use a little more compartmentalization. A Connor or Aston might be the ticket. The most comfortable packs I've used, and the Ute for load bearing is hands down the best thing I've put on my back ever. The harness they have...

1.425 for the 174.

Jackets on the VT's will generally be thicker than Vmax of the same caliber. The Vmaxs are usually shot in stuff that's like 1:10-1:14" twist barrels. The VT's are more like 1:7-1:10 and at 3000+fps the risk of blowing up warranted it. That said, in most circumstances you're going to get...

The image that the erector tube "sees" is generated at the objective lens. It's usually not a huge difference .030-.050 depending on rail angle.

Scope over bore at the objective lens, zero (range or angle) of 10+ rounds, parallax free as precise as possible. All environmental data input to match current reality. A scope tracking test never hurts. 4DoF uses Cd vs. Mach data gathered with doppler radar over the entire Mach regime of...

If your zero, optics, and drag/dynamic models are decent, then you should be able to use accurate MV information and achieve accurate results. If you have to lie about MV to get things to line up, it's a good indication the drag model is inaccurate or your optics/zero are not accurate. YMMV.

3-groove barrel?

Yeah McCoy's book is probably what you're after. Chapter 9 has the vector differential equations for 6DoF and modified point mass trajectories.

edit: welp the link didn't work. Amazon has Robert McCoy's, Modern Exterior Ballistics: The Launch and Flight Dynamics of Symmetric Projectiles Has most of the equations you'll need I believe.

Getcha some rasps/files and take your time ;)