Blind Magazine Feeding Problems

A reader recently asked about blind magazine feeding problems in bolt-action rifles. He wrote:

First of all, I just want you to know how much I enjoy your writing, especially your mountain hunting trips. I am considering a Kimber Montana in .270 Winchester, for my lightweight, do-anything medium game rifle. I have heard, however, that rifles with blind magazines can have feeding issues. I know you have a lot of experience with ultralight hunting guns. What has been your experience with the blind magazine regarding reliability of feeding? Thank you sir, for your time, and for any information you can provide.

V/R,

Randy

Hi Randy,

Thanks for your kind words of support. And congrats on your new Kimber Montana. That’s a great pick for an easy carrying, effective field rifle. As for the 270 Winchester chambering... with the right bullets it will handle anything.

As far as I know, the Kimber Montana is the lightest controlled-round-feed action on the market. Rifles, Inc. builds lighter push feeds, as does New Ultra Light Arms, but only the Kimber is a CRF. I’ve shot and hunted with a couple of Montanas and have had no feeding issues. In fact, I’ve not had feeding issues with any rifle that I could attribute to a blind magazine. This includes a Rifles, Inc. Strata Stainless, a couple of Holland Custom M700s and a NULA M20. But let’s dig deeper in case I’ve been missing something.And please bear with me if I state the obvious. I do that so we both are absolutely clear about what a blind magazine does and how. I’ve seen manufacturers advertise their rifles as “blind magazine bolt actions with a hinged floorplate,” so there's plenty of confusion to go around.

Sleek and under 5 pounds, Rifles, Inc. Strata feeds perfectly with a blind magazine.

A blind magazine is essentially any fixed, vertically-stacked, internal box magazine (not a detachable box) without an opening in its bottom, i.e., no floorplate. A blind magazine typically includes a Z-shaped leaf spring attached to a follower plate. Spring and plate ride within a steel box open at its top and bottom and press fitted to the bottom of the receiver. This entire magazine set up is enclosed in a hollow or well within the rifle stock directly under the bolt body.

A blind magazine includes a steel box with Z-spring and steel follower. A floorplate magazine includes a metal cover hinged in front of the trigger guard.

The alternative to a blind magazine is a hinged floorplate style. It differs from the blind style in that the bottom of the well is cut through and capped with a lid, the floorplate, hinged fore and latched aft, usually under a lever in the trigger guard. When the lever is pushed to release the floorplate, it swings down, the Z-spring and follower plate come down with it and any cartridges in the magazine fall out. Essentially the hinged floorplate is a convenience and safety feature for quickly and easily emptying the magazine without having to cycle every round up, out and through the action. (There is another, simple way to safely bolt rounds out of the magazine without actually arming the rifle. We’ll describe that later.)

Opening a hinged floorplate dumps out all cartridges in the magazine. Handy for quick unloading, but problematic if the latch opens accidentally.

How Blind Magazine Works

Whether floorplate or blind, here’s how these box magazines function: Cartridges are inserted through the receiver port (top) and pressed down and fully back into the magazine until they are held by the receiver’s rear “feed lips”. Of course, the Z-spring constantly pushes the follower and cartridges against these lips and the bottom of the bolt body itself. When the bolt is fully retracted, it ends up completely behind the topmost cartridge in the magazine. This allows that cartridge to pop up just enough that the bolt head will catch the top of its base or rim. Now, as the bolt is pushed forward, the cartridge is shoved forward, nose angled slightly up, until it clears the feed lips and springs free of the magazine.

The bottom of the bolt face pushes against the top of the cartridge rim to shove it out of the magazine the same way, whether floorplate or blind.

Whew! It takes a lot longer to describe this than to do it. If the bolt is a controlled-round-feed, like the Kimber, the cartridge rim will slide up between the bolt face and the extractor hook, which holds the cartridge securely against the bolt face. You could pull the bolt back at this point and bring the cartridge with it. In fact, you could activate the bolt release and pull the bolt and cartridge completely out of the receiver as one unit.

If the bolt is a push-feed like a Remington M700 or Mossberg Patriot, the cartridge will merely lie there, loose, roughly halfway into the chamber. Bring the bolt back and the round will not come with it.

How Might Blind Magazine Feeding Problems Arise?

Now we must ask ourselves how a blind magazine might alter this process. Remember, the “blind” part means there is no hole in the belly of the stock under the magazine well. This means the base of the Z-spring usually rests against the wood or fiberglass of the stock itself, and here might be our first hint of a potential problem.

The bottom of a floorplate magazine well stock shows the space the magazine and trigger guard/bottom metal will fill. The blind magazine below hides the magazine well that's carved within it.

Topside view shows the open well of a floorplate magazine stock compared to a blind magazine stock below.

With a hinged floorplate design, the bottom of the Z-spring is secured to the floorplate. This prevents it from shifting fore or aft and side to side. Since this isn’t a feature in blind magazines, could that be the source of any feeding issues?

I doubt it. The metal magazine box within the well serves as a guide for the follower plate and Z-spring itself, preventing both from wobbling side to side. This suggests to me that rumors of blind magazine feeding problems might have resulted from someone failing to keep the metal magazine box properly press fitted to the receiver. Or maybe they lost the box completely so that the leaf-spring shifts radically within the stock well and binds. That might, indeed, inhibit proper feeding. Another possibility is that someone put the Z-spring in backward.

Conclusion

Properly constructed and maintained, a blind magazine should function and feed no worse and no better than a hinged floorplate magazine. The benefits of a blind magazine are lighter weight, fewer parts to break, and no chance that a floorplate might pop open inadvertently (heavy recoiling rifles have been known to spring them open) and spill all your cartridges.

Before I sign off, here’s my technique for emptying a blind magazine without fully loading a round into battery:

Shove the bolt forward until a cartridge springs free of the magazine. Stop before pushing the cartridge all the way into the chamber and closing the bolt. Instead, pull the bolt back and pluck or tip the cartridge out. Repeat until the magazine is empty. The rifle can't fire if the bolt isn't locked into battery. This works with push-feed and CRF actions.

Randy, regardless which rifle you get, I hope you have success with it. Good luck. And enjoy the mountains!

Ron 

Blind magazines were a mystery to Ron Spomer for years until he began studying firearms instead of just hunting with them.