B-Square Scope Mount Problem

quamnet

I just bought a B-Square scope mount for my Winchester 1300. I was sighting it in this weekend for slug season and the gun was shooting consistently 12 inches low. After making the maximum elevation adjustment to the scope I was still 8 inches low. The gunsmith at the range said that I needed a new mount lower to the gun. I don't want to pay to get the shotgun tapped, so I'd rather stick with the B-Square mount.

I have a little room to get the scope lower to the gun with smaller scope rings. Would that help or does anyone have any other suggestions?

b00mer

check to make sure the mount is not higher on front then the back, may can make some stainless or brass shims to move the rear up some, or reverse for front lower then rear

BHAVIN

Call B-Square and talk to a tech they may have some answers for you.

Guns & Glass

Problem is simple to resolve. First, the things that can cause this.

You don't indicate @ shooting distance but let's use 100 yards.



1. Slugs trajectories are like throwning footballs deep. Need a big arc for distance. AKA like lead baseballs thrown from center field. They can use up adjustments quick.

2. ALL scopes are adjustment factored from the bore center to scope center with a value of 1.50". When raising the scope center via a base mount then rings anything going over 1.50" from bore center eats up Elevation adjustments.

3.The great (I like it) B Square "saddle style" mount has an open sight arch, and has a good 'rise'.

4. Medium or higher rings Combine that with themount and Elevation adjustments fade quickly.

Don't worry about seeing the sights. Usually don't unless on low power, and then usually you can't because they're so close & fuzzy.

5. Low grade optics. I won't go into that because it can take pages.

6. Guns characteristics. They have their own POI.

7. Shooter technique. Sat w/a guy shooting a Browning BPS I set up for him and he was 12" R & 8" H. I shot the same gun right after him, 1.5" R & 3" H. It's not always the scope either

EZ & Quick Solution= Burris Signature Zee Rings with 0.20 inserts in the rear ring. Use the '0' in the front. Put the +0.20 in the ring bottom, and the -in the top. Reset scope for 'mechanical zero' (won't read that in scope instructions) and go back to the range.

You'll gained 20" of Elevation @ 100 yards, will use LESS adjustments so you may see BETTER, and there is NO stress on the tube by shimming.

select-fire

Don't know what kind of slugs you are shooting but trajectory on slugs is not that great. Sighted in at 50 yd they will drop a little more than 4" out to 100yd.

spookster

sight on the top ofthe deers back,,,and let him have it !

quamnet

I forgot to mention that it was 8 inches low at 25 yards.

I didn't even try at 100 yards given how far it was off at 25 yards.

1KYDSTR

Quamnet. I just did the exact same thing for a friend who was having trouble hitting with iron sights. I bought the B'Square (I REALLY loathe these things) saddle mount, carefu;lly set it up and bore sighted it at work and took it to the range. Since Deer season is this week, I had no time to sight the gun (I'm the range boss on the 300 yd). My buddy came by, and took it to his FIL's house to shoot at a bucket. Put the bucket at 30 yards and let fly. The slug entered the bucket about 3" low and dead on windage. He corrected about 10 clicks down and went again...nothing. He loaded another, and another, and another (you get the idea...these were Hornady SST's by the way) ubtil he had exhausted WAAAAAY too many slugs and gave up. Brought it back to me the next day to see if I could figure it out. It took me exactly 5 seconds to see that the rear attachment leg was split on the back side. This then loosened up the mount and rings through the next 30 rounds he fired (yeah...I know. He should have stopped at about 3) and slid the scope back in the mount whereupon he got smacked in the nose with the scope. I had no time to get another set-up for him so I had tp go to Cabela's down the street and pick up another one. This one after 20 rounds is holding up OK. I had no time to shim the rings so he is about 4" low on POI (There is less than a 32 nd of an inch rise over the mount from the bottom of the scope tube, si it is as low as it can go!)at 50 yards, and about 8" at 100. As mentioned before, aim at the crest of their shoulder and let fly, I suppose.

If these were the ONLY B-Squatre set-ups I had go south I would be OK with it. The fact I have also had an SVT-40, a 49/56 Mauser 98 mount tear themselves assunder really makes me want to tell you to forget about them. The only one I have that is still functional is the scout mount for my M-44, and all they are is a block of aluminum that replaces the rear sight...not much to go wrong there.

The 1300/1400 mount is a piss poor design. If you look at the holes drilled for the rear pin attachment, they left WAAAAY too little metal on the screw head side. They drill across the rear of the mount legs at the rear corners, and the counter drill the screw head tolerance. The threaded end has about an eighth of an inch behind it. The screw head side, with the counter sink has less than a sixteenth...I leave it to you to decide whether or not that is enough metal for something generating that kind of recoil energy; for my part it has been proven to me that it is not! I suppose they must make SOME decent products...I have yet to locate those however. Use a peep sight if you dislike the iron sights on the gun, but you are likely better off without that mount. I will post back after my buddy has related field experience with the set-up to me. I hope he gets his deer...otherwise it is back to the drawing board. I think I will reccomend something OTHER than a 1300...1 pin location in the back of the reciever seems less than ideal to me, and the B-Square mount has two Zytel plastic screws that impinge upon the front of the triggerguard for a forward purchase on the gun...what a joke.

Guns & Glass

Agree w/1KYDSTER that some B Square mounts on some guns are marginal, however the mount for the 1200,1300,1400 is more that adequate for the hunting application.

In fixing many bad set ups, I've found that TOO many times TOO much torque has been applied to the screws. It's real easy to do.
This is an aluminum mount w/STEEL screws. Once stretched beyond it's holding power the threads are ruined permanently. Shooting only loosens the joint faster, and ruins it even more. So.....someone then grabs a wrench and retightens it again....but tighter this time because they "feel" someflex. It will snug up....but it's actually damaged way beyond mechanical repair. At that point Loctite 272/273, or a Retaining Compound 603/680 will help.....for a while if the threads aren't totall stripped out.

Another area of destruction, is chemical galvanic corrosion. Steel & aluminum don't like each other, and they fight if not seperated by a insulating barrier. Galvanic corrosion occurs between the metals speeded up by wetness & humidity. Taking a gun in-out of warm to cold weather will produce 'water sweating'. Shooting in high humidity, damp, foggy weather also exposes water to the thread joint. As time goes on the aluminum thread material corrodes and thus weakens, so the mount moves....again. Loctite 222, or 242-243 is an absolute requirement under the screw head, and thread holes.

A lot of metal isn't needed around the screw, but it would look better. The recoil force is directed thru the interface between the receiver holes, and the screw shank. The steel screw could be just like the OEM steel push pins that don't even have a head or threads and work well, but the weight of the scope & mount, plus the higher mount would produce more torque, and the push pins may not stay in.

Before the 'saddle mount' many companies used only one sided mounts, which had smart leveling & recoil "Jack screws" going down from the mount top to the receiver in the front & rear. You gently screwed tham down till they touched the receiver (after the crosss bolt was tightened) with a hair more torque on the rear screw. In addition The 'saddle mount' which is a modified arch (strongest design in shapes) spreads recoil across both sides, mimimizing twist.
Years ago they used one side mounts

The Winchester shotun has only one crossbolt9Many other have two so they're much stronger) so the trigger guard screws are needed. Made usually from Zytel Delrin which are very strong super wear resistant super plastics that even car-trucks use for belt pulleys. A version of them is actually used inside scopes by some famous scope makers. Don't be concerned about it's strength.
It is critical that the screws are NOT over torqued which puts a torque twist on the mount that can loosen a mount or cause mount flex under recoil. Especially with some of the newer hotter ammo.

That model in Winchester has never been and will hardly be a very accurate slug rig due to a combination of things. It's a hunter.

Short tang barrels usually produce fair-averge accuracy due to alot less surface area, and vibration. It's not a very strong lock up.

Aluminum receiver isn't as rigid with a short tang, and the bolt vibrates and flexes which does affect accuracy.

Regarding the scope height, the critical measurement isn't just the distance between the receiver and mount, but the total height of the mount, ring, and scope. Simply measure from the barrel center to the scope center. More than 1.5" always reduces Elevation adjustment.

Example:
Scope vertical adjustment range is 30" @ 100 yds.
Bore center to scope center is 1.625" That's only 1/8" (0.125") UP.
Elevation adjustment is reduced to about 17.5" linear.
Factor in quality of optics, ANY mount/scope movement, shooter technique quality, any movement due to what the shotgun is laying on, slug ammo variations....and POI is negatively affected.

Tapping & drilling is the best way to go on this rig but cost is a personal choice. If you do, suggest using a one piece mount for this application, Loctite 222 Purple, or 242/243 Blue is an absolute.

All in all, if done right the saddle mount is a good cost effective set up. Have done quite a few, and will do more. Your issue may not be with the mount integrity, but rather the optical system.