Rimfire auto's that shoot Short & Long Rifle intermixed

[dhenzler]

I have recently purchased three Remington model 552's. I've been installing my 2lb or 3lb trigger spring in them with great success. However had one that was giving me trouble firing anything. Hammer strike noise heard, but no BANG followed it... This rifle probably the youngest in the batch was pretty clean when it arrived, and I dismissed the thought of taking it apart for a thorough cleaning and lube.

Ultimately I took it apart one more time and gave the bore a shot of solvent, and ran a paper towel patch down it from the muzzle, and pushed out a glob of black gook. It now shoots fine

Have had some interest in the floating chamber concept used in the model 550-1's and thought that might be the reason. However did not see any sign of a floating anything near the rear of the barrel. I have NOT attempted to fire any shorts, but the idea that it does was interesting none the less.

A few Youtube videos make mention that the 552 is the ONLY rimfire auto that shoots the mixed shorts long and long rifle cartridges. Me thinks NOT SO... as the Nylon 66 touts the same, and the 550-1 the same... and likely some others.

Am writing the Topic to receive some knowledge and clarification as to what is, and what isn't. And how the 552 shoots the mix. An avid Remington collector I have one of each models that I found particularly interesting, some times more. I found the late production 552's to be pretty nice rifles. So have added more to the wall... Someone who knows... please set me straight.

Dave

[Mainspring]

And how the 552 shoots the mix.

The blow-back design requires enough power/oomph from the cartridge to cycle the action. The oomph needs to overcome the weight of the parts and spring tension that are in the way of the empty case moving rearward. The bullet is already gone and the pressure gone before parts start moving rearward with any significance, this is with parts in proper working order. Pressure works both ways, pushing the bullet forward and the bolt rearward, the bullet being lighter in weight moves easier and faster than the bolt. The "trick" is to keep the bolt forward long enough to prevent pressure from rupturing a case yet still allow proper extraction/ejection/feeding.

The 550-1 uses a heavier bolt, increased mass, to keep the case from rupturing. But the .22 Short cartridge is not powerful enough to overcome the mass. By using a floating chamber the mass of the empty Short case is increased, this extra mass provides more power to move the bolt rearward. Too much mass/power/oomph moving rearward will beat the gun to death. The more powerful Long and Long Rifle cartridge, if used with a floating chamber, would absolutely beat the gun to death. To prevent this the floating chamber is short enough to only be used with the Short cartridge while the Long and Long Rifle, being a longer case, will bridge the gap between the floating and fixed chamber. When fired the pressures rise enough to lock the floating chamber in place preventing movement, thus decreasing pressures enough to prevent damage to the rifle.

The 552 does not use the floating chamber, but still has to function and not beat itself up. A lighter weight bolt reduces mass and a longer Action Spring aid in functioning with the .22 Short cartridge. Excessive energy from the bolt moving rearward is absorbed by the Bolt Buffer and Buffer Pad, which the 550-1 does not possess.

Some energy is needed in both rifles. The 552 needs to recock the Hammer while compressing the Hammer Spring, and the 550-1 needs the Mainspring compressed enough so that the Firing Pin is captured. Spring weight and travel length of springs in both models helps to achieve the balance needed for safety and function.

[dhenzler]

Thanks for the explanation. I figured it had to be a different bolt weight & spring. But the floating chamber was an interesting thing that I thought Remington used again and again.

I've considered getting a 550-1. A good friend has one that I helped him find a stock for. But the unsophisticated sights and trigger guard kinda throw me off. Admittedly I like the later models that I can use my 2 or 3lb springs in to adjust the horrible trigger pulls.

Dave

[nambujim]

I don't even know if this is worth talking about but I have a Browning Grade II .22 Auto that I purchased new in 1970, manufactured in 1968. It is of course the same design as the Remington 24/241 so I thought I would give some input on its ability to shoot both .22 Long Rifle & .22 Shorts.

We were at the range way the hell back in about 1974 when we ran out of Long Rifle ammunition, our range being about 20 miles from the nearest place you could purchase ammunition thought I would try shooting up a box of Hi-speed shorts that had been lingering in my shooting box. Tried one, shot with no problem, tried two with no problem, and then loaded the magazine which held like 17-18 "shorts". They all fired without incident.

So I know for a fact the rifle will shoot long rifle & shorts but never tried to mix them but think the odds of them working together are pretty good. Wouldn't even have thought about it except for this posting.

For info!

Jim Peterson
Charlotte, NC

[600RemGuy]

Never has the Nylon 66 ever been advertised and able to shoot anything but for what it is intended to shoot which could be the most common 22LR but gallery guns are chambered for 22 short only. The LR rifles may and likely will jam up with long or short.