“Would it be a wise move to build or use a locking type rest that would take all human error out of the process of sighting in a slug gun, except knowing when to pull the trigger?”
The issue is when you make or use this type of rest, you artificially make the gun much heavier and that, in turn, effects the amount of muzzle jump that happens during the recoil cycle. You would end up sighting the gun in at one effective gun weight/muzzle jump reading. Then when you shoot the gun at game in the field at its normal weight, it WILL shoot to a different point of aim. Because you can no longer hold the muzzle jump in the same position, at the moment the slug leaves the barrel, while hunting as it did at the range when you were sighting in.
A Caldwell Lead Sled Solo mechanical rest. Rests are a valuable adjunct for sighting-in your slug gun but don’t replicate the point of impact of a shoulder-fired weapon
This is the same issue with any gun that has significant recoil and muzzle velocities under a 1900-2000fps range. Muzzleloaders/Slug Guns are all in the same boat. The time the bullet spends moving through the barrel (dwell time) during the recoil cycle is the same amount of time that the gun is being pulled off of the target until the bullet exits the barrel.
There is a huge difference in barrel dwell time between 1900fps and guns with muzzle velocities above 3000fps, such as varmint/magnum rifles. At above 3000fps guns move less than .020ths of an inch and the bullet has already exited the muzzle and the dwell time has only a minor effect on the sighting in process. Physical recoil and developing a flinch is the main issue with those weapons.
This doesn’t even take into consideration the torque that is applied to the gun by the slug spinning upwards of 50,000rpm’s inside the barrel while the slug is moving toward the muzzle. And then there is an effect this type of zeroing would have on shooting DOWN out of a HIGH tree stand or UP along a side hill.
Putting something on your shoulder is the best you can do to help tame the recoil of a slug gun. The muzzle must be left to jump according to how hard you hold your gun at both ends. Artificially adding weight to the gun by using a weighted rest or similar fixed gun rest may only create a missed deer in the field. You must hold the slug gun in such a manner, while sighting it in, that you can duplicate it in the field while shooting at game!! That includes the amount of muzzle jump you are allowing during the sight-in and gives “Overall Consistency in how you hold/grit the weapon.”
Bottom line, there is no magic fix. You will need to sit down and take somewhat of a thumping while sighting in a slug gun! I know there is a lot of recoil reducing advertisement out there but most of it works OK with rifles. They do reduce recoil with ML/Slug guns but it can have an adverse effect on your true zero! “Let’s not miss the Buck of a Life Time!”
The Legal Stuff: All results detailed within our website’s ‘Shooting Guide’ were produced while shooting a Tar-Hunt custom rifled barrel slug gun and Lightfield sabot slugs, each a standard for accuracy within the shooting industry and together are capable of producing optimal groupings at all effective ranges. Your results will vary greatly depending upon the model gun and type of ammunition you are using, the amount of time you spend on the range, as well as other factors. We do not guarantee that you will be able to shoot one inch groups using our shooting techniques.