Description
Our High Load spring for the CZ Bren 2S and 2MS gas piston is designed to reduce the bolt velocity on both “1 – Normal” and “2 – Adverse” gas system settings. By increasing both the pre-load and spring rate acting on the gas piston rod we are able to delay the unlock time of the carrier and bolt, which in turn reduces the pressure in the barrel at unlock and ultimately reduces bolt velocity. This is a direct replacement for the factory piston spring (#10 on factory manuals).
We have tested many different piston spring designs with ALL current 556×45 and 762×39 Bren 2S and 2MS configurations/barrel lengths. We selected this particular design because it maintains 100% reliability in all weapons tested with all ammunition tested.
With our High Load spring installed you can expect to see more consistent ejection from the 8″-11″ guns and less gas at the ejection port from all barrel lengths.
- Reduced Bolt Velocity
- Direct Fit for Bren 2S and 2MS in 556×45 and 762×39
Designed and Manufactured completely in USA.
Gunsmith Installation Recommended for All Parts.
Don Sebesta III (verified owner) –
High quality, consistent tension. Def feels like it slows down bolt velocity. Should’ve bought another for spares! No issues after about 75rds. That’s all I did tonight
Derek Kozelka (verified owner) –
Easy to install. Not sure if I was supposed too but the factory spring is stuck on there pretty good because the very top part of the spring is bent in just a tiny bit to catch in the groove holding it in place. I ended up doing this same thing and it snapped into place and holds in the factory groove. Gonna try it out soon but seems to be a nice product.
bigdkozelka (verified owner) –
Update
While I didn’t have issues with my pistol prior I installed the spring anyway and now the ejection after comparing through videos is a perfect 3 O’clock and much more consistent than before. Recoil impulse seems to be a bit lighter as well. For 7$ I feel its sort of dumb not to order the spring if you plan to order some other parts. Just add it to your cart and install as it improved even a non troublesome Bren 2. Nice product HB and thank you for helping the platform.
Sam Seefeldt (verified owner) –
This heavier spring seemed to help a bit. Noticeably less felt recoil (less bolt speed) but still having FTE issues. Extraction is great if the gun is ran by hand. Not 100 percent sure if a smaller gas port is needed or just a heavier spring. Any suggestions HBI?
14″ barrel 7.62×39
pmazon5000 (verified owner) –
CZ Bren 2MS 16” Barrel, 5.56
Another great addition to the rifle, I picked one up because the rifle was seeming to cycle really hard. So why not? I used some powder puff frangible stuff, that seldom cycles both M4s and AR-15s. I had exactly zero issues and the brass came out pleasantly, but positively.
I have been continuously impressed with the products from HBI, and I look forward to other innovative items.
brightt (verified owner) –
I don’t get why someone gave this product 3/5 stars because they got a lemon bren 2. my 11in 7.62×39 has been flawless.
product is a mandatory upgrade imo. like most of hb industries offerings
Lance Dacus (verified owner) –
Put the new spring in awhile back, have had absolutely no more problems with my Bren, 11”, 7.62×39. Runs all day without anymore double feeds or ejection problems, thanks HB for a simple product that fixed a major issue CZ USA should’ve already resolved for people. It’s good the industry has companies like HB industries around!!!
Sam (verified owner) –
I installed the spring thinking it was $7 and worth trying out just for the sake of experimentation. I installed it in my 14” 223 pistol.
While shooting, I never had any issues feeding, extracting, or ejecting. The gun cycled exactly as it should.
However, about half the time, the gun would fail to lock open on an empty magazine. I tested it with both Okay Industries aluminum magazines and Gen 2 Pmags. Both experiences a failure to lock open at about the same rate. I was using GGG 55 gr 223.
I can’t say whether it reduces felt recoil, I did not shoot it side by side with the OEM piston spring.
chen zheng –
Note that if you run a HBI drilled gas port with a low pressure can alone with this strong spring, the gun will short stroke with lower powered 223 (russian) ammo.
Kurt (verified owner) –
Have not shot it yet, but install wasn’t as hard as others described. The OEM spring is tight, and seats into a notch in piston. Just expand the spring (pull down), and use needle nose pliers to lift out spring end from the notch. It will come out without mis forming it. New spring slides on without issue. Just be aware of the additional effort that will be needed to re assemble the gas assembly.