Bench testing pump action slug shotguns

[GLC]

How do you go about bench testing a slug gun to find out its accuracy potential?

I have a Remington 870 pump and this is what I do:

I put the bottom of the receiver (near the bottom loading gate) on top of my Hart rifle rest and use a sand filled "bunny ear" bag at the back. When shooting, I hold firmly down on the forearm to control the "jump." I find that this works best for me.

I've seen many put the forearm right on the rest. Seems to me that there would be a lot of movement there.

How do you do it to get the best, most consistant results? Any suggestions?

[Ramrod]

GLC, Your method probably works as well as any other for comparing one load against another as to group size. But I would not trust the sighting-in zero you get for use in the field. Here you should lose the rear bag, get a firm grip on the gun, and rest the back of the off-hand on the front bag. Let the gun recoil more normally. I think you will find some differance in where the slug goes. This applies to any hard kicking gun.

[GLC]

I agree with not trusting the bench zero completely.  I usually zero on the bench and finish by shooting kneeling and standing off hand as if I'm hunting so I am confident where it will hit in the field.  

I'll give your method a try too to see how it compares.  

Thanks.