how to adjust cast, drop, and LOP on an 870P

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Chris17404

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Nov 30, 2005
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Location
York, PA
Hi all,

My 870P does not currently fit me very well, but I'd like to continue using it for skeet as I learn the basics, improve, and until I can purchase a dedicated clay-shooting gun in the future.

I am 6'3" tall, 200lbs, with long arms. I believe I need to adjust the cast (to the right), drop the comb a little, and increase LOP.

How would you suggest I do that on my 870P? What can I do myself versus having a gunfitter custom fit it?

Thanks in advance for your "on topic" replies.

Chris
 
I'd recommend a competent gunfitter. Most will prefer to actually watch you shoot. If one has a Try Gun, that would be Great!!

Even so, a seasoned shooter can assist. IF can try to shoot some other folks' guns similar in build to you. One can get actual measurments and perhaps a suggestion on a competent smith to do this as well.

I am guessing you wear a 34"-35" sleeve, so yes for skeet a longer LOP would help. Do you shoot Low Gun or Pre- Mount? If Low gun, I recommend toe/ heel be taken down and the inside of recoil pad be Contoured. Pachmyr Decelarator is all I ever recommend.

One "can" use shims to adjust cast. Fitters actually "bend" the stock.

Drop gets tricky as wood is removed. Measure thrice , rasp once. Also the width and how top is finished is important. For instance one does not want too "sharp" but more "rounded"...

Recall also as the LOP is changed, drop, cast , pitch changes too. I'd try a slip on pad to see if that gets close to LOP, notice how these other dimensions change as well.

Hopefully someone will know of someone at your club, or someone here on THR will know of someone near you.

Gun fit, good for you for recognizing the need for and considerations.

Best of Luck-

Steve
 
I won't get into the specifics of an 870, since those guns generally fit me pretty well and there are others here with far more experience making modifications. I do, however, have a fair bit of experience with modifying other stocks for fit. First of all, if you have any woodworking or mechanical skills at all, it's not a bad project. Second, it's an 870. Even if you totally botch it, replacement stocks are readily available and relatively affordable.

All this being said, having a gun fit to you is an experience I think every shotgunner should go through at least once. The prices can range from maybe $100 for a change of LOP, pitch and a recoil pad to over $1000 for a true custom fitting and a stock handmade to your dimensions.

Most importantly, I'd take it slow and make one change at a time. If you change more than one thing at a time, then you can end up not knowing what to alter if problems occur.

IMO, the first thing to get right is LOP. Coupled with this, you want to get the pitch* correct. This is also an ideal time to add a premium recoil pad (Pachmyar Decelerator, Kick-Eez, Limbsaver, etc...).

Since LOP and pitch both have an effect upon drop, make sure that you pattern it and shoot it a bit at this stage to get an idea if you need to alter the drop. If, when you pattern the gun, it is shooting low, you'll want to decrease the amount of drop. On the other hand, if it's patterning high, increase drop. Work in small increments, since it is easy to remove wood, but difficult to replace it.

I believe that Dave McCracken has posted in the past about using shims between the receiver and stock in order to change the cast (and probably the drop as well).

* Pitch is the angle of the cut at the rear of the stock. Depending upon the configuration of the shooter and the gun, it may be necessary to either increase or decrease that angle in order to provide optimum contact in the shoulder pocket. For example, my Winchester 1300 Defender naturally pointed quite high for me. When I cut the stock down a bit, I removed more material from the toe of the stock than the heel, and now it points exactly right.
 
Thanks for the great info, guys. Keep it coming.

I am considering taking Dave McC's suggestion and adding some shims to adjust cast and drop. How does one remove/replace the stock from the receiver to do this? I took a look at the 870 schematics, and I don't quite follow it. What tools do you need for the job?

Chris
 
Chris17404 said:
Thanks for the great info, guys. Keep it coming.

I am considering taking Dave McC's suggestion and adding some shims to adjust cast and drop. How does one remove/replace the stock from the receiver to do this? I took a look at the 870 schematics, and I don't quite follow it. What tools do you need for the job?

Chris
Click to expand...

I have an 870 that is going through this procedure right now. I need more drop at the comb to shoot plain-barrel'd guns. I first tried lengthening via shims under the recoil pad. I also use tapered shims to adjust the heel/toe. This did effectively lower the comb but not enough. Eventually I wound up with too long a LOP.
Now I am using wedges at the wrist/receiver. This is a much better solution (for me) as it only takes a small amount, like less than 1/8", to get good results, like nearly 1/2", where my cheek meets the stock.
Unfortunately for me though, the amount I need pushes the stock too far away from the receiver and I lose the good fit of the stock-to-receiver so I cannot keep it bolted tightly enough to keep it from loosening while shooting the sporting clay course.
It is amazing to me that a gun as popular as the 870 has no aftermarket spacers/wedges available.
I am not especially fond of modifying my stock as stocks are not forever and sooner or later, I will need to do it again. Plus, I like to restore old stocks so I am forever finding new “diamonds in the rough” for my guns. A spacer/wedge would be transferable to new stocks or even different 870s'.
Still tinkering,
Mike
 
That's exactly what I was wondering, 9mmMike... How much can you shim it before the either the bolts don't go in right, or the integrity of the connection between the receiver and the stock is compromised? I have done a pretty extensive search using Google to find any type of aftermarket shim kit for the 870, but it looks like they don't exist. I am surprised.

After learning so much recently about proper gun fit (using THR and TFL), I now realize just how badly my 870P fits me. No wonder I'm only hitting 16-18 out of 25 skeet clays. Sometimes when I miss, the guys I'm shooting with say, "Man, how did you miss that?" Now I know why.

An 870 shim kit sounds like it would sell like hot cakes!
 
Did I just answer this elsewhere?...

A shim kit might sell, but since most of us can fold aluminum foil, snip pieces off old plastic hulls and/or cut sections of shell boxes without drawing blood, maybe not very well.

Here's the procedure one more time. Use a patterning board, plate, or lock down a trap to throw straightaways and stand at post three.

A 1/16" change in the stock will move things an inch at 16 yards on the pattern plate. Shoot a couple patterns.

It won't take much of a shim to move the butt 1/16". If the pattern hits on the right, shim on the right.

But....

At the trap range, watch the breaks and adjust in the direction of the big piece. If the big piece goes right and up, add shims low and left. Once you're smoking the targets, try again with lower straightaways and see what happens.
 
Dave McCracken said:
Did I just answer this elsewhere?...

A shim kit might sell, but since most of us can fold aluminum foil, snip pieces off old plastic hulls and/or cut sections of shell boxes without drawing blood, maybe not very well.

Here's the procedure one more time. Use a patterning board, plate, or lock down a trap to throw straightaways and stand at post three.

A 1/16" change in the stock will move things an inch at 16 yards on the pattern plate. Shoot a couple patterns.

It won't take much of a shim to move the butt 1/16". If the pattern hits on the right, shim on the right.

But....

At the trap range, watch the breaks and adjust in the direction of the big piece. If the big piece goes right and up, add shims low and left. Once you're smoking the targets, try again with lower straightaways and see what happens.
Click to expand...


Hi Dave. This thread is everywhere! LOL

For me at least, we're talking about a different kind of "fit". I am trying to get the gun to stop hurting me when I shoot. I need a much more radical change. What you're describing is, for me, the fine tuning that I might do to get the pattern where I want it. I'm not ready for that yet. I just want to shoot a round of SC without a swollen and bruised cheek.
 
Thanks for the info, Dave. I have been reading many of your posts on gun fit in THR and TFL, and I have learned quite a bit from you. Thanks a lot for your sharing your experience and insight.

I have to say that I'm in the same boat as 9mmMike. I, too, have been coming home with a bruised cheek after shooting just a few rounds of skeet. I tried Dave's suggestion of looking at a point, closing my eyes, mounting my gun, and then seeing where it's pointing. When I do this, it's way off to the left and high. I also have long arms, and find myself scrunching my hand to get only my fingertip on the trigger.

I need to add cast off, add some drop, and increase LOP... probably fix the pitch too. I've found some good products on Brownell's website that will help me adjust LOP and pitch. Go here:

http://www.brownells.com/aspx/ns/store/catsearch.aspx?c=994&p=3953

As for cast and drop, I am going to try adding some cut-up spent hulls temporarily, but I was also thinking about going to Lowe's and finding some sort of thin polymer/plastic sheets that I could trace the receiver on, cut out, and then sand down to make some make-shift shims. I'll let you know how it goes.

Chris
 
You're welcome, Chris. Please keep us posted, maybe some others will take heed and benefit thereby.
 
DaveMcC, 9mmMike... here's on update:

I successfully modified the cast of my 870P. It's a really good feeling when you can do something yourself! I basically took Dave McC's advise. Here's what I did:

1. Cut up an empty Winchester AA hull into a piece of plastic about 1 inch long and about 1/2 inch wide. Then I folded it in half lengthwise. This resulted in a shim 1 inch by 1/4 inch and about 1/8 - 3/16 in thickness (when fully installed and pressed together).

2. I loosened the stock bolt (but did not remove it).

3. I slid the shim into the left side of the stock, vertically, between the stock bearing plate and the wood stock.

4. Then, making sure it stayed put, I slowly tightened the stock bolt again.

Voila! This resulted in a very nice, secure fit between the stock and receiver. There is a space on the left side that is not flush, but that was to be expected. The resulting cast-off is about a full inch at the end of my recoil pad (R3 pad).

The stock fits me A LOT better now. My eye is directly behind the receiver and the beads line up!

Next step is to adjust the drop. Once I found out how easy it was to adjust the cast, I did experiment and tried adjusting drop the same way using a shim. It worked fairly well, but it took away some of the cast that I added simply because the additional shim on the top of the receiver was further to the right, thus reducing the cast angle.

Next, I need to adust the drop and LOP.

I am planning to get an adjustable butt plate that I can use to increase the drop. Anyone have a recommendation for this? Ideally, I'd like to use my existing Remington R3 recoil pad with it. To adjust LOP (I need to add about a full inch or so), I may be able to use the same adjustable butt plate, or maybe add a spacer between the butt plate and the recoil pad. Recommendations?

That's it! I am a happy camper! I can't wait to try shooting skeet with my newly modified 870.

One other thing... I am considering purchasing a Remington 1100 for skeet also. Does anyone know if the same stock shimming (to adjust cast) will work with an 1100?

Thanks again to Dave McC for his knowledge!

Chris
 
Remember that an 1100 has its recoil mechanism in the stock - adjust the stock too much, and you'll bend the recoil mechanism. This is known in the trade as Not A Good Thing...
 
I've used Morgans, their pads are non interchangeable with others sans major surgery.

The Jones pad has up to 1 1/2" of drop, most others have an inch at most.

Add spacers first, that will increase drop.

Do shoot it now and see how things go. You may experience a slump in your scores until you adjust.

If you go further with the mods, do one at a time.

HTH, and you're very welcome...
 
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