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The Blaser R8 is quite a rifle. Its interchangeable barrel and bolt system enables a relative quick caliber swap, from the demure (if speedy and accurate) .222 Remington to the monstrous (if monstrous) .500 Jeffery. [Click here for an X-Ray look at how the R8’s caliber-change system works.] As Nick recently pronounced – whilst installing a UTM RBT Target Shooting Kit in an AR – modularity has been the disruptive technology in the rifle biz. Consumers who used to buy finished modern sporting rifles are now rolling their own from parts produced hither and yon. In the world of handguns . . .

SIG SAUER’s modular P320 and [full-size] P250 offer a quick caliber change. The guns are selling well but they haven’t exactly set the world on fire, perhaps because of their price or consumer awareness. But it’s the continuation of a modular handgun trend – born of a desire to shoot cheaper ammo in a gun with a higher caliber – which has a bright future. How modular are you?

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  1. Modularity sounded like a great idea to me. I bought bolt guns with interchangeable barrels. I bought single shot guns that could change calibers and even shot gun barrels. I bought multiple AR uppers to stick on just one AR lower. I ended up buying whole bolt guns for all of those barrels. I ended up buying several single shots, each with their own barrel, and now almost all of my ARs are whole ARs with matching uppers and lowers.
    Changing the parts wasn’t the big hassle, keeping track of them and making sure I had them whenever I would need them was. So was making sure I had the right ammunition. It has just been easier to have the whole gun to grab it and go.

    • I ended up buying lowers for all my AR uppers. Modularity is just the new gateway drug to a walk in gun safe room.

      “Just try the 300BLK upper, you can swap it out…”

      Next thing you know the tooth fairy is a meth head and your daughters knocked up seen it a thousand times.

  2. lack of awareness maybe?
    mr. nevins told me to buy the 320 in .45 so you can caliber down. apparently some of the smaller cal’s won’t trade up…

  3. Heck, I’ve been going modular with handguns since 1979 . . . Thompson Center Contender, with barrels from .22LR up to .357 Herrett and .44 mag. Still have it, and it’s by far the most accurate handgun I’ve ever shot.

    Really wish I could get a 10″ barrel for it in .300 Blackout, tapped for a scope and threaded for a can. Would make a great whitetail or hog gun . . . .

    • Yeah,
      The TC Contender, and it’s companion are great guns. I have a Contender with custom very heavy fore-end in 223 Rem. that will shoot under an inch. at 100 yds. Not every group, and not every day. The gun is much to heavy to hunt with, but great on the bench.
      I’m wondering why you would want such a short barrel in 300 blackout. wouldn’t a 14″ barrel give you better performance??

      • Well, Leghorn’s the .300 Blackout authority here, but my understanding is that subsonic .300 Blackout rounds are optimized for about an 8″ barrel . . . not to mention that a decent can is gonna add another 6″ or so to the OAL.

        With a good can, I’m thinking such a setup would be very quiet. Of course, you’d also have to go with a bull barrel profile to support the can, so unless you have arms like Popeye shooting it offhand would be quite a trick.

  4. My modules, nodules, family jewels, and all my other ‘ules are firmly affixed and permanently attached. Otherwise I’d loose them.

  5. Wait a minute.
    On a bolt gun, the scope is mounted on the barrel. The barrel is also the serialized part, generally, so I have to think that a second bolt/barrel set will have its own ATF paperwork.

    It may be quick to swap out the bolt and barrel on a rifle, but what do you gain? You still need to mount the scope and sight it in. The only thing you save is the stock. Why not just buy the whole gun, mount a scope and be done with it? The utility of this is lost on me.

    As for Sig’s modular handgun system – It’s a neat concept but it’s hard enough keeping track of my guns. I’d hate to have to keep track of more parts for guns. I’d rather shoot than spend my time swapping out parts while trying not to lose any.

    I do like the concept of converting and AR from .223 to .300 Blackout (and back), but that’s a different deal.

    • “The barrel is also the serialized part”
      No, the barrel is not required to be serialized and is rarely “the serialized part”.

      As for the scope, you don’t have to have one. Or you could just have one for each barrel.

      • Bausch & Lomb, many years ago made a scope mount with windage and elevation adjustments. They also made a scope without any adjustments for use with this mount. Never owned one, but I always thought it was a good idea.
        You could have any number of rifles and only one scope.
        Don’t know if anybody now makes a similar set-up?

    • Receiver is usually the serialized part (the “gun”) Scopes usually mount to the receiver. You would of course have to rezero your scope for your different loads.

      Some rifles have 2 receivers (AR-15 for example has both Upper & Lower receiver.) — AR-15 Lower is the serialized part. Barrel screws into the upper receiver – Scope mounts to the top of the receiver. (on the AR usually through a Picatinny Rail) —

      Conventional bolt action rifles the Receiver would be drilled and tapped for the scope mounts.

      Top view of the remington 700 receiver – the bolt would enter from the rear, the scope mounts would be affixed to the screw holes in the top – barrel would screw into the front.

  6. I’d like to be more modular but the guns that are most attractive to me are often the least modular. The AR-15 is the only/most modular gun I have.

  7. I have watched the flimsy trigger/magazine of a brand new R8 get a hairline crack when loading it which led to the gun malfunctioning. Gun would not fire and then everything just fell out of the rifle…

    Hopefully just that particular rifle but after watching that I would not buy an expensive rifle like that. Extra magazines are very expensive as are the scope mounts. Basically not worth the cost.

  8. I just don’t understand the purpose of modular firearms. If you want to shoot other size bullets, buy another gun. I suspect, but don’t know, that the tradeoffs to allow modularity impact some functionality.

    I suppose it’s more feasible with pistols, but for rifles the arduous task of zeroing the rifle every time you swap something takes any benefit away. With pistols the sights are never that critical, but for rifles it is imperative.

    • “More feasible with pistols”? I suppose so, but what for? The only reason I can think of is to practice with .22LR, extremely cheap practice, since you can’t find any, with whatever gun you are actually going to carry. Personally, I prefer to practice with what I’m going to use for real, which is why I’m high on Train and Defend ammo, they shoot the same. OTOH, if you’re shooting a .45, why in the world would you want to modular over to a .40? Just ain’t that much difference. Or a 9mm.

  9. Skylar – Modular guns address a need for people who live in states (or countries) with highly restrictive rules on gun ownership. They may not be able to own guns in every cabliber they want to shoot or carry.

  10. I’ve never been to Africa, and don’t want to go, but I think spending thousands of dollars on maybe a once in a lifetime hunt, and only bringing one rifle, even if it does have modular capabilities, is about the dumbest thing I can think of.

    • Yes. As I understand it, this is the first rifle ever produced with a manually operated safety that can be quickly switched off to fire.

  11. Modularity is the opposite of tactical. I live in Australia so I’m not up to speed on ARs etc, but if I had the option I’d settle for 2 guns. Fast twist 223 carbine, and a medium weight 20″ bolt gun in 260.

    No magazine issues, no cartridge recognition issues, just one decision to make, am I shooting two legs or four?

    As is, I’ll be content to train on shooting far and fast.

  12. I’ve been bitten. My workmate is in to the 80 percent lower thing – unregistered DlY. I checked and the dies for the vice and router are $200 with the 80’s costing more than the stripped lowers on sale (last one’s $50 ea). So last Thanksgiving sale bought an Anderson lower and Delton complete kits sans lower, 223. Put it together shoots fine. Had to buy a rear sight. Total cost about $550. Recently used the two lowers I bought to make a 6.8 SPC (Rock River complete upper for $515) so the cost was $665 +tax & DROS. Waiting on delivery of a 300blkout from ARMil-Spec for $384-completed cost $534! I didn’t go the 80 percent thing because of the costs and I am already registered in CA for multiple firearms. So no good trying to go unregistered.


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