Super heavy guide rod experiment. 5.4oz

[earlan357]

A few weeks ago I started experimenting with modifying my CZ P-10F to use a large diameter tungsten guide rod and 1911 springs.  It came out to 3.2oz and runs great.  Since I had 6" of tungsten rod leftover, I made a .400" diameter rod for my Gen5 G34.    I had to narrow the front portion slightly to get it in the slide, otherwise the base would hang on the barrel lugs.  I've got the large spring from the OEM RSA in as a place holder and I still need to polish out the tool marks.  The recoil spring I plan to use will be here tomorrow.  Weight is 5.4oz.  An X300 with batteries is 4.3oz.  The factory frame alone weighs 5.2oz.

 

 

 

 

Edited December 5, 2019 by earlan357
pics

[cjmill87]

Incredible work, definitely following for results!

[Beef15]

That's impressive.

[CharlieD]

Very intriguing, keep us posted and let me know when I can order one.

[Yondering]

Interesting stuff. How well does that tungsten machine? Looks like you got a nice finish on it so it must not be too bad. I machine a lot of stainless and titanium but haven't worked with tungsten yet. 

[earlan357]

2 hours ago, Yondering said:

Interesting stuff. How well does that tungsten machine? Looks like you got a nice finish on it so it must not be too bad. I machine a lot of stainless and titanium but haven't worked with tungsten yet. 

 

I used a 90% tungsten, 6% nickel, 4% copper alloy.  Higher % tungsten is too brittle.  This stuff wears tooling like cast iron.  Sharp carbide inserts with positive rake is a must or the metal will just displace instead of cut.  I've seen recommendations of 200-300 SFM, but I ran mine at about 100 SFM.  886 RPM, .004 IPR, taking off .020" per pass down to .420" diameter.  Finishing pass at .002 IPR to the final diameter of .400".  I should've waited to use the new carbide insert until the last two passes.  I got a much nicer finish on a test section when the insert was new and sharp.  Sandpaper and Scotchbrite are pretty ineffective at removing toolmarks.   I've got some 0.5-15  micron diamond lapping paste on the way to slick it up more.

[OdinIII]

You need to sell these!

[tha1000]

that's pretty boss.

[lacivilian]

8 minutes ago, tha1000 said:

that's pretty boss.

See if you can buy one.

[sweetback]

You need to sell these!

[mwx40x40]

18 minutes ago, sweetback said:

You need to sell these!

^^^^^

[Dwbsig]

Would love to get one.

[Intheshaw1]

I'd be interested in one as well.

[earlan357]

I'm not really planning to sell these, but if I was, they'd have to be made to order and I'd have to charge about $150 to break even. That's assuming it even works.  I'm still waiting on the springs.  1/2" tungsten rod is $12/ft.  It takes about 6" of material and an hour of shop time($70/hr), plus it requires a lot more than sanding/polishing to get them smooth compared to stainless.  Regular automotive sandpaper barely scratches tungsten.  I have to use multiple grits of diamond lapping compound and a leather strop on a bench lathe to smooth it out.  On top of that, I can only get about two guide rods out of a carbide lathe insert, so the tooling costs adds another $10 per rod.

 

It goes without saying that this is only for competition guns.  I have two longevity concerns.  One is the barrel impacting down on the rod/spring everytime the barrel unlocks.  Like oem, the rod floats freely in the frame so the only real damage would be to the base(same diameter as OEM).  That's where the marks on the bottom of the barrel come from with the factory RSA, and it's why you always get little chips in the base of metal guide rods.  Second, that rod has a lot of inertia, so as the slide cycles and the muzzle  lifts, I wonder how much extra stress it's putting on the rod and slide tunnel.  It would suck to have to replace the rod every few thousand rounds due to wear, or worse, wear on the slide tunnel.  Tungsten alloy is harder than stainless steel, though not as hard as melonite/nitride, and more brittle but the nickel and copper should add enough resilience to prevent breakage.  Springs are round-wire and will need replacing more frequently than flat-wire or OEM, but I changed to Wolff round-wire springs years ago, and change my springs every 5-6K anyway so that doesn't bother me.  

Springs should arrive today.  My plan is to get a few thousand rounds and maybe a few local indoor matches done.  Also need to see how much the extra weight effects my transitions and index.  I switched back from my 43oz steel framed CZ because I had to decelerate my wide transitions sooner to avoid overshooting the A-zone, but I loved how flat it shot and how the muzzle heaviness seemed more natural to index.

[Yondering]

21 hours ago, earlan357 said:

 

I used a 90% tungsten, 6% nickel, 4% copper alloy.  Higher % tungsten is too brittle.  This stuff wears tooling like cast iron.  Sharp carbide inserts with positive rake is a must or the metal will just displace instead of cut.  I've seen recommendations of 200-300 SFM, but I ran mine at about 100 SFM.  886 RPM, .004 IPR, taking off .020" per pass down to .420" diameter.  Finishing pass at .002 IPR to the final diameter of .400".  I should've waited to use the new carbide insert until the last two passes.  I got a much nicer finish on a test section when the insert was new and sharp.  Sandpaper and Scotchbrite are pretty ineffective at removing toolmarks.   I've got some 0.5-15  micron diamond lapping paste on the way to slick it up more.

 

Thanks, that's good info. Looks like your feeds and speeds aren't too much different than some stainless alloys. 

 

What is that tungsten alloy called, and where did you buy it? I can see how that'd be useful material for a few different things.

 

[earlan357]

28 minutes ago, Yondering said:

 

Thanks, that's good info. Looks like your feeds and speeds aren't too much different than some stainless alloys. 

 

What is that tungsten alloy called, and where did you buy it? I can see how that'd be useful material for a few different things.

 

Our shop buys tungsten in bulk from Midwest Tungsten.  They sell smaller amounts on Amazon: https://amzn.to/2RxXMKR

[earlan357]

So the spring arrived yesterday.  It's a 14# XD-M spring from Wolff.  The wire diameter is .046" and it has 19 coils.  The coils were binding and limiting travel by .078", so I had to clip a few off.  I made a .050" thick adapter ring from Delrin.  The spring seat area on the G34 isn't a complete circle, so I wanted something to keep the front coil flat.  The Delrin ring also reduces the slide's .437" inner diameter to .412" , eliminating rod (.402") to slide contact, and providing better alignment.  It's pretty smooth, but I still need to polish the rod.  My diamond lapping paste arrives today.  The spring's outside diameter is .515".  The OEM is .500".  The barrel makes a little contact with the spring as it drops to unlock, but no more than it did with the factory RSA.  I ended up taking 2.5 coils off the spring and it feels just slightly heavier than the 13# spring I had in it earlier.  Will adjust after test-fire tomorrow.

Since I can't stop experimenting I also reduced the angle on the striker leg by 9 degrees in the mill.  According to my math, I can take up to 15 degrees off the sear nose without it bumping the trigger bar down, but the new angle would make the sear leg too short.  At 9 degrees, I still had to slightly bend up the trigger bar cruciform to maintain about 3/4 sear engagement. Not sure how long it will last since I cut through the factory finish, but both the striker leg and sear nose are mirror polished so I think I'll be able to get a full season out of it (6-8k rounds plus dry-fire).   Coupled with a 6# trigger spring, a 4# Striker spring, and an OEM 4.5 "dot" connector, the pull weight is down to 2.5#.  About 1# of take-up to the wall and doesn't have the mushiness you get with 3.5 connectors.  There's a ton of overtravel though so I'll probably pick up a Ghost 4.5 CAT connector to dial it out.  With the OEM "'-" connector it breaks just over 2#.

 

 

 

 

 

[earlan357]

Polished up the rod with 3.5, 1.0, and 0.5 micron diamond lapping paste yesterday.  Then shot 150 rounds and got my optic zeroed with my standard 147gr 132PF loads.  Mostly B-8s at distance and a few Bill drills.  No malfunctions, brass landing about 4 feet to my right.  Sights returned a little high, but I haven't undercut the trigger guard or reduced the backstrap hump so my index was high to begin with.  The slide felt sluggish on the return stroke, almost like it was pausing for a beat and I was waiting for it to start going back into battery.  Odd because the slide cycles super smooth.  It's almost like the slide is a few oz too heavy. I've got another 14# and a heavier 16# spring on order to play with.  This morning I thinned the base from .150" to .075") to make more room for the spring so I won't have to clip as many coils off.  I'm also going to replace the Delrin adapter ring with an aluminum one that I can make thinner.  Since both ends of the Wolff spring are closed, I don't actually need the ring, but it acts as a bushing to keep the rod from touching the slide.  I also have a CHPWS optic plate arriving today.  Being aluminum, it weighs about 0.5 oz less than the factory steel MOS plate, so we'll see how much of an effect that makes.  This is fun.

Edited December 10, 2019 by earlan357

[Paul49]

Do you think there is friction between the rod and the bushing that slows down the slide? Could the springs be binding on the thick rod?

[earlan357]

1 hour ago, Paul49 said:

Do you think there is friction between the rod and the bushing that slows down the slide? Could the springs be binding on the thick rod?

The bushing in there now is Delrin which is a low friction polymer.  I used plastic since it was just for short-term testing and easy to machine.  The rod is polished smooth, and the spring is oversized to the rod by only .021" so the coils stay pretty much straight. Coil springs expand when compressed, so there's even more clearance as the slide retracts.  With the connector and barrel removed there's barely any noise coming from the rod/spring.  No tightness/roughness in the slide-frame rails either and the ejector is not dragging on the slide center rib.  Really the most felt resistance comes from the connector riding against the slide as it cams on and off the disconnector surfaces.

OEM springs are thinner wire, so they can stack up a lot more coils.  They utilize more pre-load since the force increases at a lower rate.  I had to clip a few coils off the XDM spring.  Otherwise, the coils would stack up and prevent the slide from retracting fully.  This lowers pre-load, but increases spring rate.  Interestingly, according to my calculations, due to the helix angle and thickness of the wire, the spring peak force actually gets about 3% stronger with each coil removed up to a point.  Hopefully the 16# spring has a lower coil count and the extra space I added for the rod will be enough.

Edited December 9, 2019 by earlan357

[Eman]

Have you tried 124gr loads in the 132 power factor? I know my Springfield range officer 1911 slide was super sluggish with my 147gr 130pf loads, and the 124’s were just right. My g34 likes 147’s better though with a 13# recoil spring. Maybe try some factory 115’s as well to see slide cycle speeds. I am very interested in your findings! Good work!

[earlan357]

52 minutes ago, Eman said:

Have you tried 124gr loads in the 132 power factor? I know my Springfield range officer 1911 slide was super sluggish with my 147gr 130pf loads, and the 124’s were just right. My g34 likes 147’s better though with a 13# recoil spring. Maybe try some factory 115’s as well to see slide cycle speeds. I am very interested in your findings! Good work!

I plan to try 125gr.  I don't reload, I just buy minor reman from Outdoor Dynamics.  I have some 125 on custom order but there's a lead time of a few weeks.  I tried 124s with my gen3 G34 a while back and I also found I preferred the 147s with a 13# spring.  I shot one magazine of 147gr Blazer Brass (~147PF) yesterday and didn't notice any sluggishness.  I don't think I've owned a striker fired gun that didn't prefer 147gr.  I think it has something to do with not having a hammer to help delay the slide/barrel unlock timing.  But who knows, with the g19 style barrel lugs and different slide weight, maybe the gen5 will buck that trend.

My hunch is that I'm going to need to lighten the slide a bit.  I plan to get front serrations cut anyways. I'm hoping that and a front top pocket will be enough, but I'll resort to windows if I have to.

[earlan357]

I shot a match over the weekend with the trimmed 14# Wolff XDM spring(minus 1 coil).  The only malfunction I had was user induced when I failed to fully seat the mag on a reload.  It was running fine so I didn’t try the 16# spring (minus 2.5 coils) until afterwards.  I ran some bill drills with the 16# and slide returned flatter but casings weren’t ejecting as far, landing just 2 to 3 feet away.

[Tikly]

Please sell this, if you do contact me Tikly.Tahir@hotmail.com

[BillChunn]

@earlan357Really nice work on the tungsten and thanks for posting your research results.  To put things in perspective, Springer Precision is selling a 3.4 ounce tungsten guide rod for the Sig P320 Legion for $125.00.  The Legion also uses a tungsten infused grip so the guide rod seems to balance out the gun and reduces muzzle climb during recoil.

 

BC

Edited January 14, 2021 by BillChunn