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Robert's 17HMR Magnum Build

16K views 147 replies 14 participants last post by  tanakasan 
#1 · (Edited)
Robert's 17HMR Razor Magnum Build

Well, I got the chance to machine my Razor receiver and bolt today!

Also, I was surprised at how light the recoil spring is!:eek: I have found a like sized replacement but with twice the rating. The SF spring is around 62# rating, the possible replacement is 124#.

Also going to machine a long brass follower. The SF follower is 5g, the joiner (not really coupled mass) is 3g. I am thinking that a 3" long follower should add a few grams to the bolt mass. SF charging handle by itself is 22g. Going to see how much mass I can add...can't hurt, right? I was surprised that brass is slightly more dense that stainless steel! Learn something every day!

I did not install my KID +10% spring. If these mods are successful, I would rather anyone else not *have* to add another item.

Will keep adding to this post as I go along, any comments or suggestions welcome!

Robert

Here we go again!


Indicated within .0005 over 4~5"


Barrel hole location within .001


Final drill operation, stepped up over a few sizes


.6875 reamer ready


Done


Looks good!


.1875 ream for TG holes


Numbers look familiar?


V-block threads


5/16" magazine hole @ 3 degrees


Milling the bolt shelf (about .050~.060) so the bolt will drop in easy


Enlarging the pocket on the bolt face


Fits a lot better now

Not much came out


Fits and stays great
 
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#122 ·
Hey Brian!

No, just the last outing, but was the 22WMR setup. How is the mallory bolt handle coming along? I think I need to go there next and do the bolt & handle.

Your setup is just inside the threshold for reliable shooting. Mine seems just outside...shoots well, but still has the occasional kaboom. Loads well, cycles great but getting the battle of the bulge still. The extra mallory mass is the difference I believe!

Not sure if my 16" barrel is helping or hurting. Might get another 20" to compare.

Keep us posted on the bolt handle!:bthumb:

Robert
 
#123 ·
I haven't been able to make it. I threw my back out the Sunday before last, then again on last Friday, and spent the past weekend in the Hospital because I couldn't even stand. So as soon as I heal up a little I'll get back on it.

But I have to admit, the 17 hmr project keeps my mind busy. If the bolt handle makes it completely reliable, I think I'm going to need another project. But I have considered sending the barrel out to have it ported and maybe have the receiver and barrel coated. Basically keep the project growing.

We'll see, first things first. Keep us updated on your project.
 
#130 ·
^^Likewise, Brian! Hope you are healing up real good and out shootin' again!!:AR15firin

Thought I would update the thread with current (final?) pics of the build.

Now shooting 22WMR through a 20" GM blued fluted 77/22 barrel. Using a KID +10% recoil rod spring (thanks Brian) and a 5-7/8" length of med (.040) mainspring in the Razor Magnum receiver. Custom heavy bolt handle and long SST follower.

The rifle just shoots now. No issues, no bulges, no blowouts, no feed/fire issues using CCI 40 gr FMJ and Fiocchi 40gr JHP and Ruger 10 round mags. It does not like the blunt nose on the Win 45gr Dyna Points at all.

SelectFire Razor Magnum is a fun and rewarding build!:bthumb:

Robert



 
#131 ·
I'm still kicking, lol. Thanks for the concern guys. I'm still off work, but feeling much better. I wasn't able to shoot for about 4-5 weeks (or do anything else), but I have been out a few times in the past 2 weeks. I did take my 17 out 2 weeks ago, but was only able to shoot 50 rounds before the range closed, it is still shooting perfectly with CCI 20 grain. I picked up some Hornady 20 grain for it, but haven't had a chance to try it out, and I still haven't made my Mallory bolt handle yet.

I did pick up a Savage 12 in 300wsm, that will be my next project. It will be getting a muzzle brake and custom stock w/a detachable magazine and custom cerakote/durakote.

My Dad and I made a dueling target stand for pistols yesterday, that thing is a lot of fun. We put about 300 rounds in it yesterday, and the 3/8" steel just shrugged off 9,38,40, and 357.

So Robert, when are you going to throw your 17 barrel on and try it again?
 
#132 · (Edited)
Good to hear you're better!

Not sure if the HMR will be resurrected...this one is shooting perfectly.

With the 17, it was always "holding your breath" waiting for a rim blowout or exploding mag. The rim not so bad (have had a "few" so far) but the exploding mag still spooks me. Had my arm been there, it would have been ugly.

If I get the urge for another 17, might be a CZ 455 bolt. Right now, just having a blast with the 22WMR Razor. Got a great deal on some ammo...kinda hard to beat the $$/fun value!

Dueling trees are fun! How big are your targets? Too bad I don't live closer!

Robert
 
#135 ·
My brother is friends with some guys who own a shop that have waterjet's and laser cutter's, either would be fine. The targets are crude, so either way would be more accurate than my needs. The plates that are on it now were cut with a plasma, and they work fine. I only have $70 in the stand that I built, and that's with 3/8" steel, that's cheap compared to some that I have seen professionally built. The target is at my cousin's house, I will take some pics the next time I go out to shoot it.
 
#136 ·
$70 total is a good deal!

That includes the steel? Pics next time out would be great! I like seeing pics of other's shooting "ranges". I am always in awe of those lucky enough to shoot in their backyards or in some gorgeous grassy or wooded areas with mountain views in the distance.

I am lucky enough to have a standard outdoor range 15 minutes away. No shootin' in my backyard around here! The sheriff's would be here in an instant!

Robert
 
#137 ·
Yep, $70 for everything. I bought the steel from a local recycling company that charges scrap rate of .54 cents/lb., and they have a big selection that's organized very well. I had $4 in the wood base, $36 in the steel ( angle iron, round tube, 3/8" plate), and $30 to cut the plates with a plasma. It probably took me 6 hours to build. It took a while to cut, weld, debur and assemble, but it is a lot of fun.
 
#138 ·
I found out the hard way this weekend that 1/2" plate wont stand up to FMJ AK rounds at 75yds.....:rolleyes:
I built some swinging plates for a friend who has city boys come shoot at his home range and I figured the 1/2" would be plenty,boy was I wrong.They look like swiss cheese now.But one thing cool about being friends with a guy who has rich friends is the offer to shoot some wild guns,just for being there.FA is awesome!One day I will save enough to buy me one of those.
 
#139 ·
Well, after seeing Brian/stukpedal's heavy handle starting to crack, thought I would check mine and update my thread!

So far, so good. I am shooting 22WMR, not 17HMR as Brian is. I would think a lot more stress from the HMR.

We have been going back and forth trying to help each other get the HMR to shoot reliably. His was doing great, a lot better than mine due to the additional weight of the mallory metal in his bolt.

Hopefully, he will get to try the additional bolt mass added and let us know how it performs!

Reference link to my 22LR Razor build

Robert
 
#145 ·
Hey Robert, I would like to buy some of the .040" springs that you bought, but I can't find them on Mcmaster Carr's website. I contacted Jones Spring Company, and they have a $25 minimum order, which means I would end up buying 80 (or so) springs. If I have to buy them I will, but I would prefer to buy 5 of them. If you have a Mcmaster Carr part #, would you mind letting me know what it is? Thanks
 
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