Can you tune an adjustable gas block to a specific ammo?

I’m very new to the AR platform, but picked up a slick little 6.5 Grendel a while back. I’ve tried a few different ammo to see what it liked and ended up liking the Alexander Arms 129gr SST the best without my can. None of the ammo I tried grouped with my can on it. I recently put an adjustable gas block on it to possibly fix that. I have yet to shoot it with the AGB, but was wondering if I could tune it towards a different ammo? Mainly for ease of buying off the shelf at the local shop, which has the Normandy black 123gr eld.

As far as tuning the ammo to the rifle for accuracy, no. But you can tune the gas block to the ammo you are shooting for proper cycling and ejection. You want ejection in the 3 to 4 o'clock position. Some ammo may be hotter and some ammo may be less hot, which you may need to tune the gas block. In an AR, the gas block is there to dial in the cycling and ejection, not tuning the ammo's accuracy to the rifle.

This.

The gas block controls ejection timing. It does nothing for the rifle/ammo impact consistency.

Thanks for clearing that up for me. I had a very basic understanding of it, but that helped a lot.

I don’t mind sticking with that Alexander Arms ammo if that’s what it’ll like with my can, but it’s $11 a box more. The hornady black was around 1.25 moa where the AA 129sst was down around .75 moa. I couldn’t get anything to group with the can on it, which is why a couple folks recommended me getting an adjustable gas block. I mean it was like 2-3 moa with a non-adjustable gas block and the casings were nasty dirty and flinging every which direction. I don’t shoot this thing a whole lot, but I’m hoping to if I can get it dialed in with my can and this new AGB.

Suppressors dirty up brass, action, and bolt. That's all there is to it, nothing you can do about it. Clean and oil the action and bolt every chance you get.

When you add the suppressor, 2 things happens. 1- you are hanging a weight on the end of the barrel and this can change the barrel harmonics. Generally, a can helps quiet down the barrel harmonics and allow it to shoot better. But on an AR, you could be putting stress on the barrel mating to the upper. Also, if the threading is not perfectly straight, the can would not be mounted straight and cause accuracy issues. I have personally seen this issue. 2- a suppressor adds about 3K to 5K psi to the round. So it changes up the pressure of the round and can change up the accuracy.

On the ammo side of things, you can use a slow burning, double base powder that maximizes the velocity. But in an AR, this slower burning powder can cause issues with pressure and cycling. Meaning the timing of the burning powder with the gas block and bullet exiting the barrel. I've seen AR's shoot horrible with really slow burning powders, but switch powders to a fast burning powder with the same exact bullet, and groups tighten up a lot. It wouldn't surprise me if that ammo is with a really slow burning powder to try to get the most velocity, but have issues with the burn rate. AR's can be very finicky on what they like. I try to work with certain powders with an AR to reduce this issue.

Yes sir. I’ve heard that a lot lol. One guy I was talking to showed me how to field strip it and clean it when I first took it out to shoot. Like I said, I’m an AR noob to the core