gjersy

Since they came out this last March, iv'e been wanting one of these semi-auto .17HMR's. Almost bought one then, but only time will tell if any new design will be good, so waited a bit. Wondering if anyone has one and how they like it?

Sheridan

The only thing I have heard, is that .17HMR do not cycle well in semi-autos.

However, I don't say that from personal experience !

My .17HMR is a boltgun & it shoots lights out

gjersy

Thats what i heard also, and supposably Savage fixed the problem with a delayed blow back design. I'd hate to spend over $400 and get jams. Hopefully someone on the forum has put a bunch of rounds threw one, and knows about them.

CalHunter

I don't own and haven't shot one but it sounds like it would be a fun gun if it worked properly.

Nomercy448

That's been the crux of the 17HMR semiauto issue since the beginning, which is why all of them have been pulled off of the market.

If the action is light enough to cycle with such a low weight bullet and small gas expansion ratio, then it's too light to keep the action closed long enough to depressure to a safe limit, so your 10/17 Mag blows the magazine out the bottom when it opens. If it's heavy enough to keep the bolt in battery throughout the peak pressure, then it's too heavy to let the action fully cycle due to the light bullets.

Savage's new design for the A17 promises to fix that issue.

The A17, unlike the 10/17, is not a straight blowback action. The A17 has an interrupted blowback design with a camming locking bolt, such that it sustains positive lock up when chamber pressure is still high, then has a light enough bolt and spring to allow the tiny 17cal bullets to fully cycle the action. In essence, the A17 lets your have your cake and eat it too.

If/when they put a heavy barrel on top, and a laminate stock on bottom, I'll be adding one to my rimfire arsenal - and another one after that if they ever figure out how to make that apply to the 17WSM!

super_hunt54

Sounds like the new A17 action is similar to the AR.

Nomercy448

It's actually not at all related to an AR action.

Watch the video on their site and you'll see a computer generated operational model and how it works.

Savage A17 Product Video

The AR is a gas operated, direct impingement, delayed cycle rotating bolt action. Bullet fires down the barrel, pressing backwards against the locked bolt. Once it passes the gas port, gasses purge back to the action to drive the BCG rearward, camming the bolt to rotate, and unlocking the action to allow it to fully cycle rearward.

The A17 is an interrupted (different somewhat than "delayed") blowback action. There's no gas system, no rotating parts - it has a sliding locking bolt that rides a camming track.

Think about a 10/22 or Marlin 60 blowback bolt, with a sliding locking bolt somewhat akin to the Marlin 336 action, but the locking bolt is on an icy hill. The blowback of the case presses the bolt backwards, which presses the locking bolt against the receiver, providing extra resistance to the bolt at the beginning of the pressure curve. Once that pressure subsides, the camming action on the locking bolt lets it slide down into the bolt, unlocking it, and allowing it to fly under standard blowback pressures and cycle.

Contrasting to recoil-operated actions (think semiauto centerfire pistols), it has the unique characteristic that the entire chamber and barrel assembly doesn't move, so the lock-up pressure can be independently manipulated separately from bolt weight and cycle strength (spring strength), and of course, getting a recoil-operated tip barrel to run with a 20" tube is kinda challenging

Although it's more complicated than the straight blowback action, it's a blissfully simple design, that should be quite versatile for load compatibility, as well as relatively easily tuned if it ever misbehaves or if you ever go off-map, but it's not like anything modern that I've ever worked on (and I'd assume not like anything historical either, since they did get a few patents around this particular action).

super_hunt54

Ahh okay, hadn't seen the vid. Your further description also helped But I see the difference now.

Nomercy448

Can ya tell that I'm pretty pumped about a FUNCTIONAL 17HMR semi-auto rifle???

I had a 10/17 Mag for a short time, blew the mag out the bottom twice, sent it back, got another one, blew the mag out, got a heavier bolt handle = FTE, got a heavier spring = FTE, sent it back again, got a 10/22 Mag, and was happy - yet disappointed that I had failed in the endeavor to have a semiauto 17HMR.

Once they pretty this up into a stainless model with a heavy barrel and a laminate stock, tack on another $100 if they feel they have to, then I'll be on this like white on rice!

gjersy

Well i purchased the A17 a few weeks ago, put a Vortex Crossfire 2, 3-9x40 on it, cleaned it up and have put over a 100 rounds threw it. I had one mis-fire, but no jams or any other problems. The guy i bought it from said they did have to send 1 or 2 back due to jamming issues, but Savage fixed the problems. I did by the recommended A17 ammo for it and was told to keep the gun clean. I sure do love this little gun, so far so good.