Pictures of shortened BRNO .375H&H - Added range report with velocities

Hey Vern,
I've been waiting for this post to see how it would turn out. It looks good!! and it should be just the berries for those unwelcome encounters. Did you have the lop measured? it sure seemed a little long, looking forward to the range report. I just got my 9.3x62 in the CZ 550 medium mag lux and Im really happy with it.
Dave:)
 
Dave

I just got it back last night and haven't measured the barrel. it's supposed to be 20".

I'll take out the tape measure tonight and see how long it is.

The fun will start at the range this weekend! I think I'll wear ear plugs under my ear muffs for this range test.
 
Are you calling the guy with a .375 H&H carbine a sissy?

Huh Punk!!!!! :D

Errrrr, I will be wearing my PAST recoil shield when I shoot the carbine. :redface:
 
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Geologist,
I imagine you will be taking those sharp,finger abrading permanant swivels off since you have the barrel band? I've got the 550 Safari Magnum version in .375 H&H and find the recoil OK. The swivel would draw blood though. It's the only rifle that I ever shortened the stock on. The original LOP was 14 1/4", way to long for me.

Dogleg
 
Crazy Davey

Yeah I'd probably only get 10 cents on the dollar for it now that I've ruined it by cutting the barrel. :rolleyes:

I'd love to try it out on some gophers!

I'd aim at the ground just below the gopher and try to launch it into the air.:p
 
geologist said:
Crazy Davey

Yeah I'd probably only get 10 cents on the dollar for it now that I've ruined it by cutting the barrel.
Click to expand...

Well, I would give you more than that, but not much more :D

I cant believe you would do that to such a nice rifle ;) ;) :D

Kidding of course :D. Cant wait to hear your range report tomorow :)
 
Looks good. Did you chrono it before? It would be interesting to see the before & after results. I have a 602 in .458wm but I can't bring myself to cut the barrel as after I 'play' with it a while I may put it up for sale.
 
I didn't get to the range :(

Weekend chores and a last minute work thing got in the way,

I'll try to go one night this week or I'll play hooky.

I hate when my job gets in the way of my hobbies :D

I measured the barrel and it is 20". The long magnum action makes it almost as long as my unmodified BRNO 600 30-06.
 
geologist,

Glad to see you went ahead & got the .375 shortened...it looks suh-weet! Thanks for posting the pictures.

Best wishes, Jeff/1911.
 
BRNO 602 shortened barrel range report with velocities

I finally got to the range today and tested the ZKK 602 carbine.

Chronograph setup was 20' from muzzle. I started at 15' but the chrony didn't seem to like the muzzle blast :)

Federal Power Shok 270 gr SP:

25" barrel: 3 shot average: 2700 fps

20" barrel: 8 shot average: 2638 fps

Velocity loss: 62 fps

Winchester Supreme 270 gr Fail Safe: I didn't test this load prior to shortening the barrel so I'm listing the factory data. :(

24" barrel: 2670 fps

20" barrel: 3 shot average: 2599 fps

Estimated velocity loss: 71 fps

The recoil from the carbine was stout from the bench. Even with the Past recoil shield, a dozen rounds was about all my shoulder would take.

I tested it with a Bausch & Lombe 3200 3x9 in Warne QD's. I grabbed this off of my BRNO ZKK 600 30-06. It is more scope than I want for the carbine and I am still dithering on which scope to go with.

I was very surprised by the shift in POI from the ZKK600 to ZKK602.

It required 78 clicks up and 15 clicks right to get it to shoot +2.5" at 100 yards.

By the time I got it dialed in I was starting to flinch so I will accuracy test the carbine the next time I get to the range.

The 3200 has decent eye relief but I still felt a very light scope kiss on one shot.

I am leaning towards a Leupold VXII 2x7 but am tempted to go with a cheaper 3200 2x7 32mm Firefly.

Conclusions:

The average velocity loss resulting from shortening the barrel from 25" to 20" was 66 FPS.

The recoil and muzzle blast is strong but manageable, especially when shooting off hand. The muzzle flash was visible in bright sunlight and may be a factor in low light conditions.

The carbine points and handles much better than the rifle. The LOP seems to be fine as is.

The express sights seem to be printing absurdly low at 100 yards with the 100 yard leaf. It's probably my inexperience using express sights. I am going to experiment with different bead sight pictures at 25 yards before I do anything drastic. If I decide to replace the present front brass bead, I'll probably just go with a lower sight with a slightly larger brass or white bead.

I am very pleased with how this high powered carbine turned out. :D
 
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Hey geologist, good testing info. I'm amazed the drop in velocity was as minimal as it was. I expected it would be considerably more.
The barrel on my .458wm 602 is full length but I'm experiencing the opposite. The front sight is easily removed but I haven't found a source of supply for a higher replacement. What I've done in the meantime is 'glue' a piece of 0.100" fibre optic on the top. Perfect!! It'll do until I can locate an appropiate replacement.
If I keep it I plan to mount a Leupold 1x4 Vari-XII. Good eye relief on Leupold XV-III 2.5-8x36mm so that's another option.
 
Why not? said:
By any chance did you chronograph a few rounds before the bobjob to compare to after?

My bet is you lose not a lot more than 50 fps going from 26 to 20 inches with factory 300 gr ammo.

Ted
Click to expand...

So the velocity loss with 270 gr loads was 62 fps, and it certainly won't be any more with 300s.

So much for the naysayers who have never tried it. This is one of those cases of seeing is believing. The only reason I knew it would be so low is I have done two 375 to 20" like this myself and seen another one shortened by a friend of mine.

They sure are noisy though, eh? :D

Ted
 
Good stuff - the na-sayers are wrong again.

The Leupold 1.75-6X is worth considering. I've got one for my wife's '06 with a German #1 post reticle - this is another good outfit for up close work.
 
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