Mossberg 500 Fit & Patterning

Overview

I suspect this is going to become a collection of bits and pieces over time. I'm basically using this as a paper exercise to work through the issues I face getting this shotgun setup for wing shooting.

1st Fit and Pattern Test

I have a Mossberg 500 Turkey gun. 24" smooth bore vent rib barrel and camo finish. Bought it a long time ago and never used it for Turkey hunting. It was shipped with a choke set for the 835 which doesn't fit the 500. The one installed choke is a flush fit Modified.

I've used this gun for chasing upland game birds around and breaking clays. I've known for some time that the gun doesn't fit me, but I didn't care as I just don't play with shotguns in a serious manner. Recently, I watched a couple YouTube videos on stock fit and realized that I could get more enjoyment out of my pop-gun with a few tweaks. To that end I ordered a stock spacer kit off of Ebay, as Mossberg doesn't offer them anymore.

The kit consists of 4 spacers marked (L - R), -1/4, +1/8, +1/4, +3/8. The spacers adjust drop only and I would imagine that a person could very carefully add a little cast by carefully sanding a spacer as they are made of a very hard plastic. Note that the closed top is what goes to the top of the stock, the numbered end goes to the bottom.

Side view showing the shape of each (left goes toward the top of the stock)

I'm not sure who the stock shotgun is supposed to fit. I'm 3' 37" tall and found that I needed to increase the drop. So I installed the -1/4 spacer (leftmost above). This greatly improved my cheek/eye placement. I also added a little close cell foam in front of the butt pad to bring the length of pull out to the "2 knuckles" thumb to eye.

I'm kind of interested in seeing if I can use this gun for water fowl, so I thought I'd try the following shells

The 7 1/2 shot target loads are what I typically throw at clays, so it seemed like a good idea to see how they patterned.

Kent Fasteel is super popular around here. I grabbed the only two shot sizes on the store shelf. I also grabbed a box of Remington steel #4.

In the following pictures of shot patterns, the width of the paper is 30" and height is a little more. The "M" stands for "Modified Choke". "#3", for example, is the shot size, and "40yd" or "30yd" are the distances.

You can draw a mental circle around the shot cluster. I suppose you can also draw in a Mallard if you want. Since this was my very first time patterning, I wasn't too concerned. I'm getting a full choke for this shotgun so I will try patterning it again. Next time I will have a proper paper frame at least 40" wide and I'll draw 30" circles and count pellets. I think I'll also run these loads over the chronograph.

So after staring at the previous photos, I've come to a few conclusions:

• 1. Definitely need a bigger piece of paper or cardboard. Probably at least 40" to allow for shooter boo-boos and room to visualize the main cluster. Not sure where I'm going to find this stuff.

  2. 40 yards is a long ways for a shotgun. 30 yards is pretty close. I suspect that I've been breaking clays all these years with one or two pellets when I let that clay sail out there 50yds.

  3. My 40 yard patterns seem a little iffy to me. Got to look up the lethality index and count pellets before trying to whack a duck. I don't feel comfortable with these load/choke combos.

  4. I've got more work to do just to make sure I know where the gun is pointing for wingshooting. It sure would be nice to have a lazer for this.

Second Sight In and Patterning

I did some more reading on the net about shotgun sighting in and figured out that the drop space I used was in the wrong direction and would cause me to over-compensate which would cause erratic high/low shooting (exactly what I discovered when busting clays).

So I got some 48" craft paper for my pattern work.

I fired 3 shots of Remington standard 7 1/2 shot at 30 yds and 22yds (couldn't find a spot to stand at exactly 20yds). I changed the drop shim from -1/4 to +1/4. -1/4 was too low for me, and +1/4 was way too high. +1/8 is what I settled on. I tried to do this shooting by pointing at a reference object on the ground below the paper and then swinging up and firing when I though right. Like I said, I did this 3 times at each range to get a pattern to develop. I did this with a full-choke.

Here's my target setup. Top of the paper is at 7', botton is at 3', width is 4'.

30yds, +1/8 drop shim

22yds, +1/8 drop shim

Here's my full-choke pattern with Kent Fast Steel 3", #3 shot, at 40yds.

Still more work to do.