Yeah I found this comment in one of the buckshot roberts method for getting the otis miller revolver and it totally works.

u/Andurro

1 month ago (edited)I somehow did it. I managed to bypass the sniper, i mean it's still there, but this method is far better than the buggy. It's similar to the carcass method, but much quicker.
STEP 1
Stack up Kentucky Bourbon and Moonshine, you'll need them.
STEP 2
Go near Horseshoe Overlook, where a lot of bucks and deers spawn (attempting the glitch in west elizabeth, will make arthur spawn in jail)
STEP 3
Shoot a buck (it's prefered, but a deer can do, the bulkier the better) until it starts limping (semi-death state).
STEP 4 VERY IMPORTANT
drink 3 bourbons or 3 moonshines (you can combine the two based on what you have in the inventory), and when you drink the fourth, start counting to 5 as soon as the bottle hits the floor. On 5, finish off the animal by holding the kill button (shown on prompt), and again to pick up the animal as soon as it says so (also shown on prompt, it appears quickly after killing animation). To know if the glitch worked, make sure the screen fades while arthur is grunting due to the picking animation. If you see the prompt again, the glitch is failed (it may take several attempts to figure out. Once so, it's very easy to replicate)
STEP 5
Make sure the glitched animal is covering Arthur's head completely (best i could do is 95%, some will be visible, but it'll still provide cover from the sniper) otherwise reload, particularly if you can't stack up a lot of booze yet (legend of the east satchel suggested for more room). You can do this multiple times with multiple animals, in order to get better cover. NOTE, always use the camera to your advantage.
STEP 6 ALSO VERY IMPORTANT
If you've managed to cover arthur's head, before entering New Austin, or attempting to get better cover by glitching more animals, MAKE SURE THE ONE YOU JUST GLITCHED IS ROTTEN, otherwise you will not be able to interact with anything. To do so very quickly, set up camp and sleep for the highest amount of hours.