The Original CZ Forum
CZ LONG ARMS => VZ-58 semi auto rifle => Topic started by: huskerlrrp on August 17, 2014, 08:40:07 AM
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Hello everyone,
I'm a new owner of a VZ58 (VZ2008) from Palmetto State Armory (one of these side folders). For the money, I'm impressed. I took it to the range yesterday with some Red Army ammo and fired 20 rounds relatively slow. It was reasonably accurate, albeit 5 inches to the right. There were no feeding or firing issues. When I was finished, I found the forearm to be quite warm. I did a 20 round string as fast as I could develop a site picture and at that point the forearm was too warm to comfortably handle. I had lubed and greased the the snot out of the rifle action (so much so that I got a spray on the safety glasses 8) ) so I can't say mechanical friction had anything to do with it.
Does this platform run hotter than an AR15 and AK47, for example?
Is this normal to be hotter during in a break in period?
Does this Red Army ammo run hotter than others in your experience?
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With the stock resin furniture it gets very hot, very fast. That's normal. Gloves may help.
The bonesteel aluminum rails cool off quickly. Lots of ventilation. I've also got some rubber rail ladder inserts in exposed sections which make it easier to grab when hot.
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Probably the #1 complaint about the rifle.
You can't really get away from the heat without using
a different hand guard.
I went ahead and got the Czechpoint Polymer upper and lower hand guards
I recommend you get that and a FAB Defense grip.
We love the Wood Impregnated Plastic here mostly for looks
but not for use.
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Thanks. I will look around for a different fore end.
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Do the FAB defense hand guards run cool as well? I see they have a polymer version for about $70.
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Fab keeps the stock metal tube up top so there's really not a lot of upper HG ventilation on that. You can drill holes through that metal part, etc, to allow more air to flow through.
The VZ 58 has two ports in gas tube immediately in front of the upper handguard. However, much of the piston gas vents under that front handguard. Since it's so enclosed the heat builds up under rapid fire.
That heat is also why the Czech's switched from wood to beaver barf as well. Wood always has moisture and the upper handguards get so hot so quickly that that moisture pushes away from heat rapidly, eventually steaming/boiling, and ultimately cracks the wood...
Best value all things considered is probably bonesteel. Only bonesteel and NEA/Troy cowitness w/ irons. All other foregrips do not.
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I have the FAB/Zahal fore arm and a FAB/Zahal vertical foregrip. That way the heat doesn't affect me, but the down blowing gas leaves a black smear on my hand. :) I can live with that. Yep, the one weakness of the vz-58 system is that it heats up fast.
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I'm running the NEA set with a stubby vertical grip to get my hand away from the heat. Works great!! I only like a vertical grip on the smallest of rifles.
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Just reiterating. The beaver barf sure do run hot. Earlier this year I was with some family and we ran about 300 rounds through one of my rifles in less than an hour doing pretty quick shooting. No mag dumps really. Thing got smokey and hot there really quick. Even with gloves after a while we had to set the the gun down to cool. Oven mitts would work well. O0
Any of the decent aluminum handguards made by Bonesteel, FAB, NEA, B&T, etc are fine options and will do great. Especially if you run some kind of vertical grip. No heat issues. I've never really seen any big negatives with the polymer handguards. The ones from FAB and CAA are good options for the money. And retain zero. They only issue I'd be worried about is if you do a crap load of mag dumps in a row and have sustained, high heat. I've never heard of a polymer handguard melt on vz. 58. But I've seen at least one melt on an AK.
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Just reiterating. The beaver barf sure do run hot. Earlier this year I was with some family and we ran about 300 rounds through one of my rifles in less than an hour doing pretty quick shooting. No mag dumps really. Thing got smokey and hot there really quick. Even with gloves after a while we had to set the the gun down to cool. Oven mitts would work well. O0
Any of the decent aluminum handguards made by Bonesteel, FAB, NEA, B&T, etc are fine options and will do great. Especially if you run some kind of vertical grip. No heat issues. I've never really seen any big negatives with the polymer handguards. The ones from FAB and CAA are good options for the money. And retain zero. They only issue I'd be worried about is if you do a crap load of mag dumps in a row and have sustained, high heat. I've never heard of a polymer handguard melt on vz. 58. But I've seen at least one melt on an AK.
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FWIW, I run an AFG and gas pedal on my NEA -- it's more narrow than bonesteel.
With bonesteel, on backorder, I plan to just run the afg with rail ladders. We'll see if that works!
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I run an AFG and gas pedal on my NEA
Do you have any pics of this set up?
I strongly considered that road but was unsure about the look
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For illustrative purposes. This pick doesn't have the gas pedal. But here's a pic I pulled off the web of the NEA rail with an AFG:
(http://i75.photobucket.com/albums/i302/Master_Mold/nea_zpsa3a5e87d.jpg) (http://s75.photobucket.com/user/Master_Mold/media/nea_zpsa3a5e87d.jpg.html)
I use and AFG2, but use a set of Bonesteel railed handguards:
(http://i75.photobucket.com/albums/i302/Master_Mold/DSC01590_zpscf9d35d9.jpg) (http://s75.photobucket.com/user/Master_Mold/media/DSC01590_zpscf9d35d9.jpg.html)
(http://i75.photobucket.com/albums/i302/Master_Mold/DSC01591_zpsea8f2155.jpg) (http://s75.photobucket.com/user/Master_Mold/media/DSC01591_zpsea8f2155.jpg.html)
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Here's how the AFG w/ gaspedal is setup on NEA (sorry crappy phone pic I took awhile back):
(http://oi62.tinypic.com/24w6fjo.jpg)
Don't have my reddot on in this pic, and the gaspedal is a polymer airsoft one but haven't had any issues. Their aluminum ones in FDE have been sold out for some time.
With the short rail on lower, the bottom front hole is open for ventilation, and partial of the left front is open too. There's also a small hole on the upper handguard immediately above piston that ventilates too and helps the heat to flow up. Right side the front 3 holes are covered with a short rail section as well (I use a QD flashlight mount here, otherwise it's blank).
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Someone mentioned drilling holes in the upper handguard to allow more air flow and hot gas to vent better.
Anyone actually try this?
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I mentioned that you could drill holes in the upper handguard metal tube when switching over ot a mako polymer forend. Their upper has "ventilation" holes, but since keeping the stock upper handguard tube, it actually provides no ventilation...
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I mentioned that you could drill holes in the upper handguard metal tube when switching over ot a mako polymer forend. Their upper has "ventilation" holes, but since keeping the stock upper handguard tube, it actually provides no ventilation...
What about drilling holes in the factory beaver-barf upper hand guard to ventilate? I was thinking that some holes in the apex of the curvature on both sides, a roughly 45* "V" pattern if you were to be looking down the muzzle. That way, vented gases wouldn't blur the sight picture as it may if the holes pointed straight up -- although the thought of a blurred sight picture is just speculation and I have no idea if that would actually happen.
Also, I thought of covering the inside of the lower hand guard with protective thermal tape. I use it on my spark plugs to prevent them from getting melted by the headers. Before, I had a dead spark plug every few weeks. Now, no problems. The headers are about 1/4" from the spark plug boot and run continuously at about 450* F at idle. They probably get even hotter with spirited driving.
My concern with the protective thermal tape, however, is that instead of being vented or even warming up the lower hand guard, the heat will be trapped around the barrel instead. Anyone know if that trapped heat is enough to be detrimental to accuracy or barrel life?
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Ventilated handguards work in two ways on the VZ. One is basic convection, heat flowing from upper to lower. So for this to work as best as possible, you'd want steady holes across the bottom and slightly bigger volume/area holes across the top -- heat increases volume...
The second way is just merely by not trapping the heat in there -- less using convection to cool the barrel and more just allowing the exhaust gases a place to go.
I believe bonesteel has holes in the location you mention if not slightly forward. (Though I believe they're advertised as for set screws for stability/repeat zero. Don't have BS HGs yet to see if it's stable w/o them.)
NEA has a hole immediately above the piston, with the underside contoured so that hotter gases are encouraged to exit through that hole by the force of convection, as well as through the side gaps between upper and lower. That's why non-cowitness handguards definitely provide more cooling but worse sight picture, a compromise.
Now if we really wanted a perfect CZ, we'd have a slightly taller front sight assembly (1/2-1") and run the full sized handguards providing ample ventilation on both the top and bottom.
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Ventilated handguards work in two ways on the VZ. One is basic convection, heat flowing from upper to lower. So for this to work as best as possible, you'd want steady holes across the bottom and slightly bigger volume/area holes across the top -- heat increases volume...
The second way is just merely by not trapping the heat in there -- less using convection to cool the barrel and more just allowing the exhaust gases a place to go.
I believe bonesteel has holes in the location you mention if not slightly forward. (Though I believe they're advertised as for set screws for stability/repeat zero. Don't have BS HGs yet to see if it's stable w/o them.)
NEA has a hole immediately above the piston, with the underside contoured so that hotter gases are encouraged to exit through that hole by the force of convection, as well as through the side gaps between upper and lower. That's why non-cowitness handguards definitely provide more cooling but worse sight picture, a compromise.
Now if we really wanted a perfect CZ, we'd have a slightly taller front sight assembly (1/2-1") and run the full sized handguards providing ample ventilation on both the top and bottom.
Thanks, some good info.
What do you think about the thermal tape on the lower hand guard? It should minimize heat transferred to the hand, but if that heat doesn't go somewhere it will remain, at least for a while. Will that lingering heat be detrimental?
Also, if drilling the original beaver barf, wouldn't holes in the top hand guard be sufficient? Heat rises, although that is probably irrelevant due to the force of the gases. I'm sure they will follow the path of least resistance no matter which way that is directed. Anyone tried drilling the factory hand guards?
What about these mods?
http://imgur.com/a/yO5NR?gallery
http://www.theakforum.net/forums/66-czechoslovakian/58103-probs-w-heat-transfer-lhg-fix.html
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I might look into drilling a couple vent holes.
Also maybe try making a heat shield, I have access to various thicknesses of aircraft aluminum.
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Thanks, some good info.
What do you think about the thermal tape on the lower hand guard? It should minimize heat transferred to the hand, but if that heat doesn't go somewhere it will remain, at least for a while. Will that lingering heat be detrimental?
Also, if drilling the original beaver barf, wouldn't holes in the top hand guard be sufficient? Heat rises, although that is probably irrelevant due to the force of the gases. I'm sure they will follow the path of least resistance no matter which way that is directed. Anyone tried drilling the factory hand guards?
What about these mods?
http://imgur.com/a/yO5NR?gallery
http://www.theakforum.net/forums/66-czechoslovakian/58103-probs-w-heat-transfer-lhg-fix.html
Good tutorials. The question is ultimately what you're trying to accomplish -- keep your hand cool or the barrel cool. If you anticipate ever needing to do a lot of rapid fire, then keeping the barrel cool will extend the life of your rifle. For relatively slow pace range shooting or hunting, then a deflector is probably sufficient.
Insofar as air circulation if wanting to mod, I'd personally drill a couple to holes in the bottom all the way down (1.5-2x the width of the hole in spacing to retain strength if in line), or you could space in jumps from side to side for better strength. Regardless, there's not a lot of air circulation with the standard setup, that's why the heat radiates through the handguard rather than flowing away through convection.
Insofar as convection, take a look at how baseboard heaters work. Basically, air will circulate on its own from bottom to top based upon energy transfer, molecule spacing, weight, etc...
The only difference w/ the VZ is that you have hot air coming directly off the barrel through the piston as well which has an affect to account for... In particular this is what ventilation is helpful for. If we just had barrel heat and not the gas port blowback, there'd be considerably less heat in the handguard.
No perfect answer here. Identify your needs and modify to meet them...
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I have an extra lower handguard that I'm going to experiment on, but before making swiss cheese out of it (measure twice, cut once), I've been browsing photos of aftermarket lower hand guards and most of them have pretty radical venting with huge holes or slots. The majority of them also have picatinny rails, which I assume are intended for some kind of additional fore grip that would keep the hand away from the heat. But then I saw this one:
http://www.vz58rifle.com/images/200000091-1088c11814/quad_rail_troy.jpg
It has no picatinny and is to be held like the original. Are those giant holes going to fry fingers? I would not think so as it's a part that's been mass produced, but mass production is not always an indication of efficacy.
I wouldn't drill the beaver barf to that extent due to compromising strength. I'd start small, test and redrill until the venting seemed adequate. I'm thinking that 4-6 holes in the lower hand guard, like the ones pictured above but much smaller (1/8"-1/4"), plus eight small holes in the upper hand guard, four on each side at the apex of the curve, would be an improvement.
Does anyone have any aftermarket lower handguards with similar aggressive venting, and holds the rifle with a standard supporting grip, and still has the skin on their fingers intact?
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The Troy/NEA quad rail is to/can be used with small sections of rail. If you read the description on that site. It says the handguards come with to rail sections. You can put them a number of places. Google "troy quad rail vz 58". I suppose you could go without a rail for a vertical/angled grip. But I'd bet most people would just buy the upper portion of the handguard. Or use a railed piece.
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I installed the fab defense plastic handguards on my VZ. Today I found some old ar handguards, so I removed the aluminum heat shield. Cut it down, and slid it under the barrel on the VZ with lower handguard still installed. Actually fits pretty good, although it is not secured well. I know it has the holes on the bottom, but I am still going to try it out. If it works, I will do a less hurried job using the 2nd ar heat shield. Just an idea to try out.
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I installed the fab defense plastic handguards on my VZ. Today I found some old ar handguards, so I removed the aluminum heat shield. Cut it down, and slid it under the barrel on the VZ with lower handguard still installed. Actually fits pretty good, although it is not secured well. I know it has the holes on the bottom, but I am still going to try it out. If it works, I will do a less hurried job using the 2nd ar heat shield. Just an idea to try out.
Looking forward to your results.
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I just couldn't stand paying 1/2 the cost of the rifle for some new aluminum hand guards before trying this.
(http://i468.photobucket.com/albums/rr50/huskerlrrp/SIG/IMG_20140913_122653_394_zps7e89f17c.jpg)
So far it's kept the heat down and the angled grip is nice for shooting. I used a cheap picatinny rail strip on the bottom and I put another rail on the right side for future use.
Now if I can take care of the fact I'm out of windage adjustment on the front sight this thing is going to be a shooter.
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An update on the ar aluminum heat shield. Worked pretty good. The top guard got warm, and the ends were hot. The lower hand guard was easy to hold. Granted it was only 6 magazines, and I also have a forward grip, but happy with the results, and it stayed in place. By the way Husker. Mine shoots right about 5 inches at 50 yds. And hit 960 gremlin free rounds
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I agree with whomever has stated already: The heat is there and it has to go somewhere, 2 main ways to relieve it- convection, or blocking it
Blocking it (with reflectors) will keep the handpieces cooler, but will keep that section of barrel hotter.
Convection with holes, or more thermally conductive handguards, will absorb the heat elsewhere, away from the barrel. Increasing surface area (pic rails) or mass of the handguards will help most.
Wear Gloves. Framers gloves are great.