Solving the shell surge

[Torbay]

Shell surge is a serious design problem that exists in the shotgun, is a problem that occurs when you need the shotgun intensively, so the risky situation.
Why no aftermarket company has taken the solution?, improving the power of the mag spring is a patch solution and do not solve the problem 100%
Possible solutions:
A action arm with delayed left arm actuator so latch opening would not take the second shell during the inertia.
Or also a right latch with the change you see in the attached picture ( REMOVED, WRONG IDEA).

[Synchronizor]

It's not that complicated; if your magazine spring isn't strong enough to feed during recoil, you use a stronger spring. Problem solved.

Remember, the 870 is essentially a semi-auto that's had its gas piston replaced with a pump. It's a sibling to Remington's 1100, 11-87, 11-96, 11-48, 878, and Sportsman 58 semi-automatic shotguns; and those all do just fine cycling faster than any shooter could work an 870.

There are two issues with your shell latch idea. First, those shell latches wouldn't allow you to load more than one shell into the magazine. Second, holding the rearmost shell in place won't do anything to keep the spring, follower, and other shells from moving inside the magazine tube, so recoil-induced feeding problems would still persist.

[Torbay]

After install the WHOLE ... THE WHOLE 45" Nordic components spring the problem persist!!! , but now just with full mag ( 7 ), with 3 shotshell inside, works quite good.
I think you are right, but the SA model has action bars?

Yes, forget my drawing, is wrong, but a delayed secondary latch opening should work.

It's not that complicated; if your magazine spring isn't strong enough to feed during recoil, you use a stronger spring. Problem solved.

Remember, the 870 is essentially a semi-auto that's had its gas piston replaced with a pump. It's a sibling to Remington's 1100, 11-87, 11-96, 11-48, 878, and Sportsman 58 semi-automatic shotguns; and those all do just fine cycling faster than any shooter could work an 870.

There are two issues with your shell latch idea. First, those shell latches wouldn't allow you to load more than one shell into the magazine. Second, holding the rearmost shell in place won't do anything to keep the spring, follower, and other shells from moving inside the magazine tube, so recoil-induced feeding problems would still persist.

[Synchronizor]

Yes, semi-autos have action bars. Here's a picture of a Remington 878 with the barrel and fore-end off:

Yes, forget my drawing, is wrong, but a delayed secondary latch opening should work.

The thing is, the 870 is a manually-operated firearm. The shell latches are directly actuated by the action bars, which are rigidly attached to the fore-arm. The latches will always move at specific points in the fore-end's travel, so if you want to delay their operation, the only way to do it is to delay working the slide.