.375 H&H barrel length comparison ... 24" vs 19.5"


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MCMXI
September 21, 2015, 01:40 PM
I recently sent a PM to H&Hhunter to ask about cutting down the barrel of my .375 H&H Mag. I'm having the entire rifle and scope dipped soon so this would be the time to do it. He has a .375 H&H with a 20" barrel and mentioned that if he were doing it again he'd go no less than 22". With this in mind, I asked a friend who has a custom X-Bolt with a 19.5" barrel to stop by so that we could compare velocity using a CED M2 chronograph. We were able to compare a factory Remington load, his handload and my handload. Here are the results. I did all of the shooting so as to have consistent rifle recoil and all shooting was prone which should result in the highest velocity. Obviously a larger test would be better since the barrels probably have other differences in addition to the length. After seeing the results below I've decided not to cut the barrel down. I consider my Talkeetna to be a 500 yard hunting rifle for mule deer, elk and whitetail so I feel that the extra 100+ fps is worth the added length.

http://thr.mcmxi.org/rifles/kimber/talkeetna/load_development/09_20_15/375_h&h_vel_comp.jpg

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Casefull
September 21, 2015, 02:22 PM
Thanks for sharing data. Less velocity loss than I would have thought. I understand you not wanting to lose the velocity.

Inebriated
September 21, 2015, 02:35 PM
Thanks for the data. When I was looking into getting a .338 vs. .375 in a 20" barrel, I ran across this (http ://www.longrangehunting.com/forums/f19/short-barrel-magnum-velocity-19346/) post with some velocity testing on the certain rifles, as the barrel was cut shorter and shorter. Interesting stuff. No .375 data there, but somewhat relevant. Eased my mind on .338 velocity out of a 20" barrel, which is the direction I ultimately went.

TTundra
September 21, 2015, 02:37 PM
Thanks for posting the data. I have a 20" 375H&H encore barrel I was debating on having made and I think for the 130+/-fps compared to the 7+ inches saved in OAL, I don't feel too bad about it now.

Scrumbag
September 21, 2015, 03:57 PM
Interesting. Think the effect is more pronounced in the smaller bore diameters.

I would expect say something like a step down in barrel length in .243W would be much more pronounced than in say .338 Federal chambered rifles

ATB, Scrummy

CraigC
September 21, 2015, 04:56 PM
It's difficult to extrapolate much from two different rifles. You can't assume that 100% of the difference between the two is the length. Chamber dimensions, throat, bore dimensions and the finish inside the bore all affect velocity. Although it's safe to say that you will lose something.

That said, I really don't see 4" as being a huge difference in handling or weight, depending on the contour.

MCMXI
September 21, 2015, 05:02 PM
It's difficult to extrapolate much from two different rifles. You can't assume that 100% of the difference between the two is the length. Chamber dimensions, throat, bore dimensions and the finish inside the bore all affect velocity. Although it's safe to say that you will lose something.

I made that point in my first post, but if you look at the results the velocity loss from the three loads is fairly consistent with only 17 fps difference.

Inebriated
September 21, 2015, 05:18 PM
You can't form hard data, no, but you can put those numbers in a ballistic program and come to the conclusion that all the shorter barrel means, is you lose a good bit of muzzle energy (~300-400 ft. lbs.), but past that, you are at a 50 yard deficit in energy across the board....

Example, the 270gr load (using Nikon SpotOn software).
Length - ME - 50y - 100y ----- 450y - 500y
20" - 3966 - 3571 - 3195 ----- 1356 - 1194
24" - 4370 - 3943 - 3537 ----- 1523 - 1341

Same trend on the other loads as well. So, if that energy is critical, get 50 yards closer.

Reloadron
September 21, 2015, 05:23 PM
Did both rifles have the same twist rate? I can't help but wonder if you would be giving up any accuracy with reducing the barrel length?

Ron

CraigC
September 21, 2015, 05:38 PM
I made that point in my first post, but if you look at the results the velocity loss from the three loads is fairly consistent with only 17 fps difference.
But cutting the Kimber's barrel could result in half as much loss as was witnessed between the two rifles. It could also be double. The only way to gain data that could be used across the board is to take one very long barrel and test it at 1" or 2" increments.

Either way, unless it's a very heavy contour (many .375's are) I don't think cutting 4" off it is a good idea if this is your long range rig. It this rifle was to be used as a relatively short range gun for dangerous African game or the great bears of the north, it would make much better sense. That said, I'd love to add two or three inches to my new .338 but my barrel stretcher is in the shop. ;)

MCMXI
September 21, 2015, 06:41 PM
Did both rifles have the same twist rate?

Both have a 1:12 twist.

jmr40
September 21, 2015, 07:01 PM
It is very common to see 25-50 fps with the same loads in different rifles with the same length barrel. While not common I've seen 130 fps difference when using 2 different rifles. I've seen individual 20" barrels shoot faster than some 22" barrels.

Larger bores lose less as a rule than shorter small bore rifles, so a 375 should work better than a 7mm or 300 mag. There is a lot of data out there where folks have started with long barrels and recorded data as they cut them shorter. But I cannot find any on a 375. The closest I can find is for a 338 and 340 mag. They lost 150 fps and 106 fps respectively between 27" and 21". The 338 lost 87 fps between 24" and 20". A 375 should be less than that.

http://www.longrangehunting.com/forums/f19/short-barrel-magnum-velocity-19346/

For poking around in thick stuff after stuff that bites back I want short, in fact if I were buying a 375 it would be a 20" barreled 375 Ruger

http://ruger.com/products/guideGun/models.html

Up close 100, even 200 fps won't matter much. Even at 300-400 yards 100 fps less isn't something that would be terribly difficult to overcome.

Reloadron
September 21, 2015, 07:08 PM
Both have a 1:12 twist.
Then all things considered if the cut barrel will still get you bullet stability the accuracy should remain the same I would reduce the length.

Ron

TTundra
September 22, 2015, 04:55 PM
http://rifleshooter.com/2013/12/300-winchester-magnum-how-does-barrel-length-change-velocity-a-16-300-win-mag/

A test a friend of mine participated in (there's quite a few out there now). A lot of changes since then, hes cut and re crowned in tests. Done a few on different calibers. Venture what you lose to what you gain. I chopped a 300 win to 22" and haven't had any deer complain after they drop, but sure do love how compact it is jumping in and out of trucks, added a folding mono chassis as well.

I will send him a note to see what he can do in doing this test with a 375H&H and see what he says. I think he'll say it may hurt too much to shoot all those different lengths, but it would be nice to see chopped every inch.

MCMXI
September 22, 2015, 06:22 PM
After looking at some ballistic charts I'm seriously thinking about cutting off 2" and having the barrel recrowned (recessed target crown). McGowen is just down the road from me and they can do it the same day but I'm hoping that they can chuck up the barrel without me having to remove it from the receiver. 20" would look weird with the stock that I have but 22" would look good and make the rifle a little more svelte. I can live with 24" but 22" would be a good compromise.

Corn-Picker
September 22, 2015, 09:15 PM
The other option would be a 375 Ruger with a 20" barrel, which would give you the ballistics of the 24" 375 H&H barrel with the handiness of the 20" barrel. One could take this too far I suppose, a 16" 378 Weatherby would probably beat the ballistics of a 24" 375 Ruger, but I wouldn't want to shoot that :eek:

jerkface11
September 22, 2015, 09:56 PM
A 16" .378 wby would be like a stick of dynamite going off in front of your face. I bet it would turn heads at the range though.

Robert
September 23, 2015, 11:16 AM
I think the 22" would still be plenty of umph to get you out as far as you want. I love my 375H&H. I have to thank/blame H&Hhunter for steering me in that direction.

MCMXI
September 25, 2015, 06:50 PM
UPDATE:

I had the barrel cut down to 22" today and had a recessed target crown cut into the muzzle. I removed the barrel band along with the front/rear iron sights and used red loctite to screw in the rear sight screw. I'm going to grind the screw head down then use a file to blend the threads with the barrel. After that I'll lap the bolt lugs and then screw the barrel back on. Head space is extremely tight at the moment (will only close on a go gauge with considerable force) so a couple of thousandths off the back of the bolt lugs should be fine. I've added a front sling swivel stud to the stock, and the rifle will be going out to be dipped early next week. This is how it looked prior to all the work being done. I'll post a few photos in a week or so to show the finished product.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/kimber_talkeetna_01.jpg

geologist
September 26, 2015, 05:15 AM
I chronied my BRNO 602 .375 H&H before I cut its 25" barrel down to 20".

I shot two loads (270 gr Federals and 300 gr something else) and IIRC the averaged velocity loss was around 90 fps.

That's not a lot of velocity lost considering how much handier my work rifle became for bush/transport use.

http://i71.photobucket.com/albums/i155/pbgeologist/IMG_5483.jpg

Accuracy wise it was still fine after shortening. I shot this group off of the bench with only a front sandbag with the 100 yard leaf at 100 yards.

http://i71.photobucket.com/albums/i155/pbgeologist/S5000033.jpg

MCMXI
September 29, 2015, 04:54 PM
UPDATE 2: The barrel has been cut down to 22" and crowned, the hole for the rear sight has been filled, the barrel band has been removed and the bolt lugs have been lapped to give close to 100% lug to receiver contact. The bolt now closes easily on a GO gauge with no perceptible movement of the bolt when closed on the gauge. The bolt won't even begin to close on a +.003" NO GO gauge. Also, a front sling stud has been added to the stock. I'll be shooting the rifle tonight before it goes out for dipping tomorrow. I'll post photos of the rifle tomorrow as it now sits along with more after dipping.

Inebriated
September 29, 2015, 05:00 PM
Sounds like a great project!

H&Hhunter
September 29, 2015, 08:02 PM
My 20" M-70 in .375H&H pushes 270 gr TSX's at a reliable 2650 to 2700 FPS depending on the powder used.

Jackal
September 29, 2015, 08:36 PM
Either way, I doubt the animal would notice the difference...

H&Hhunter
September 29, 2015, 08:43 PM
Either way, I doubt the animal would notice the difference...
Eggzacmerly.....

MCMXI
September 30, 2015, 03:36 PM
I shot three rounds this morning over the CED M2 using the same 250gr TTSX handload listed above that shot 2,762 fps a couple of weeks ago. Here are the results.

2,762 fps
2,756 fps
2,760 fps

I shot two groups last night which were ok but I think I'll be doing a bit more load development for the "new" rifle. Here's the rifle as it now sits and I'll post photos of it after dipping. I've also shown a couple of photos of the "coned" rear Talley ring which worked out great.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_22_02.jpg

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_22_03.jpg

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_22_04.jpg

horsemen61
September 30, 2015, 05:18 PM
Looks nice

Scrumbag
October 1, 2015, 08:47 AM
Surprised you ditched the barrel band but enjoy!!!

Robert
October 1, 2015, 09:32 AM
Man that is nice looking. I want to drop my Safari Express in a McMillin stock and maybe have the barrel cut down to 22" as well and remove the sights. Now you have me drooling...

jim in Anchorage
October 1, 2015, 12:54 PM
MCMXL-
Neat gun but way to shiny for me. I'd be afraid to scare every moose out of the valley with that thing.

MCMXI
October 1, 2015, 01:08 PM
Surprised you ditched the barrel band but enjoy!!!

I never liked the barrel band from day one so getting rid of that was an easy decision. I don't want to blow my own trumpet but I did an awesome job of installing the front sling swivel stud which took quite a bit of work to do properly. The stock has a very hard carbon fiber/fiberglass shell but the inside is filled with a low density foam. You would need to break the stock to have the front stud come out so I'm very pleased with how it turned out.

Robert,
So far I'm loving the look and balance of the rifle. The rifle weighs 9lb give or take an ounce as shown with the scope, rings and sling. Here are before and after photos on the same page to give you a better idea of the changes.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/kimber_talkeetna_03.jpg

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_22_07.jpg

MCMXI
October 1, 2015, 01:16 PM
Neat gun but way to shiny for me. I'd be afraid to scare every moose out of the valley with that thing.

Ha! Ha! :D That's why it's going out to be dipped today using the pattern shown below. The lightest color on the image below is the clear part on the film so the base coat will really affect how the pattern looks. I've chosen a light sandy color (almost off white) which is just a little darker than the white shown for the base coat so hopefully it'll look great and blend in well with the surroundings up here in MT.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/camo203.jpg

jim in Anchorage
October 1, 2015, 01:34 PM
So that's what dipped means!:o I would go dark gray on the base.

MCMXI
October 1, 2015, 01:44 PM
I've tried all kinds of base colors by laying the film over different items around the house. A black base looks good, a gray base is ok but the color I chose works very well. I'll show photos next week when the rifle is finished.

Gtscotty
October 1, 2015, 01:46 PM
MCMXL-
Neat gun but way to shiny for me. I'd be afraid to scare every moose out of the valley with that thing.

The funny thing is, it would probably blend in pretty well in the sage brush around here, and not look too out of place up in an oak stand down south.... There's a surprising amount of natural silver gray colors in a lot of places. I like it.

So you didn't lose any velocity at all cutting the barrel from 22 in to 20 in? I think the OP mentioned that H&Hunter said he wouldn't go under 22in barrel length on another .375, why is that? It would seem that the .375 works pretty well in a 20 in barrel.

MCMXI
October 1, 2015, 01:57 PM
So you didn't lose any velocity at all cutting the barrel from 22 in to 20 in? I think the OP mentioned that H&Hunter said he wouldn't go under 22in barrel length on another .375, why is that? It would seem that the .375 works pretty well in a 20 in barrel.

My handloads use VV N540 powder and I've noticed a slight increase in muzzle flash, although I've been shooting later in the evening when it's starting to get near dusk so maybe I never noticed it in the past :confused:. Anyway, I don't seem to have lost any velocity with my handloads but now am thinking about working up a new load using Reloder 15 with the same 250gr TTSX bullet. H&Hhunter will have to answer the question as to why he wouldn't go less than 22".

horsemen61
October 1, 2015, 02:48 PM
Cool

CraigC
October 2, 2015, 03:38 PM
Neat gun but way to shiny for me. I'd be afraid to scare every moose out of the valley with that thing.
That's an interesting comment. Perception is a funny thing. It's not shiny, it's a bead blasted matte finish. Even in the pic shown, you can see the same colors in the logs and rocks behind it. You don't have trees and rocks in Alaska? Folks head to the hills with stainless guns every year. Sometimes black is more out of place.

jim in Anchorage
October 3, 2015, 04:35 PM
That's an interesting comment. Perception is a funny thing. It's not shiny, it's a bead blasted matte finish. Even in the pic shown, you can see the same colors in the logs and rocks behind it. You don't have trees and rocks in Alaska? Folks head to the hills with stainless guns every year. Sometimes black is more out of place.
No we have no rocks in Alaska:rolleyes: It just looks shiny to me. Guess the owner agrees since he is having it dipped.

jim in Anchorage
October 3, 2015, 05:00 PM
MCMXL- What is that action? I notice it has a pre war M70 bolt root.

MCMXI
October 27, 2015, 05:28 PM
MCMXL- What is that action? I notice it has a pre war M70 bolt root.

It's the standard Kimber 8400 Magnum action which like all current Kimber actions are based on the Mauser '98 action. It's a very smooth action for sure.

As for the discussion about the look of the rifle, I really like the bead blast stainless finish and had no problem using it in that form while hunting. My decision to have it dipped was more about making it "mine" after a number of custom touches rather than my dissatisfaction with its appearance. Talking of the finish, the film that I chose (Camo203) turned out to be a total piece of Chinese crap so my friend suggested I choose something from TWN who is known for quality films. I wanted to use Under Armour Ridge Reaper but that would require UA contacting TWN on my behalf. Ultimately I settled on KUIU Verde (WTP-703) over the base coat that I had made up for my original choice. Here's the scope done in Camo203. I liked the washed out, faded look but the film stretches too much and looks terrible on the stock according to my friend.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/camo203_zeiss.jpg

As a teaser, here's the scope and barreled action done in KUIU Verde using the same base coat shown above. I'll post photos of the finished product once I get it back and its had a week to "set up".

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_dipped_initial.jpg

H&Hhunter
October 27, 2015, 08:34 PM
I'd set that thing down in the grass and never find it again!:D

tahoe2
October 28, 2015, 01:22 AM
I like it !! :D Can't wait to see the final !

Gordon
October 28, 2015, 02:43 AM
I built a Whitworth actioned .375 H&H improved (.375 Weatherby) with a 27" Lothar Walther stainless barrel with a 4.5-12x VX3 a few years ago. I stocked it in an exhibition grade Claro walnut blank I had English express style. It was my idea of a long range African Planes game or a long range elk or bear rifle. It ended up weighing 10 pounds tho which eliminated it from being a stalking rifle. It sits in the safe looking good while the two and a half pound less Remington 700 stainless in a Brown precision stock 24" .375 H&H made it to SA and Alaska and else where. Still a 27 " .375 Weatherby throws 300 grain boatails at more than 2700 fps in an accuracy load and at 10 pounds the recoil is like an 8 pound 260 grain 2700 fps load.

MCMXI
October 28, 2015, 09:46 AM
The rifle as shown with scope and sling comes in at fractionally under 9lb. I had no problem last year carrying it all around central MT mule deer hunting. Last weekend I carried a 15lb AI (not including scope, mount, bipod or sling) deer hunting, and I want my Talkeetna back ASAP. :what:

MCMXI
October 28, 2015, 04:07 PM
Here's another teaser from "the dipper". She's going to clear coat all the parts tomorrow (3 thin layers of epoxy) and I should have the rifle back by the weekend. The next photos will be the following weekend showing the reassembled rifle and scope. In case anyone's interested in this system, it's fairly labor intensive. She uses a two-part epoxy paint to prime all surfaces. Then she applies an epoxy base coat followed by dipping and finally three thin layers of epoxy clear coat to seal the film. Once done, the surface is very, very tough. My girlfriend has a rifle done by her and the finish is incredibly durable.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_dipped_stock.jpg

MCMXI
November 9, 2015, 01:37 PM
FINAL UPDATE:

So the rifle is finally done! Here's a list of the "upgrades" that I did and the "upgrades" that I had more talented folks do. For the record, the Talkeetna is a superb rifle that doesn't need upgrading but I wanted to make some changes and I'm really pleased with the results. I'll be using the rifle on a mule deer and elk hunt in just over two weeks!

DIY
Removed barrel and lapped bolt lugs
Removed rear sight and installed plug to fill hole (front sight hole was cut off when 2" was removed from barrel)
Removed barrel band
Installed sling stud in forend

OUTSOURCED
Had barrel cut down from 24" to 22" and recessed target crown added
Had cone cut into rear scope ring to match ocular bell housing
Had rifle, scope, rings, bases and scope covers dipped

As I mentioned in an earlier post, the headspace has changed fractionally. Intitially the bolt was very tight closing on a GO GAUGE whereas the bolt now closes fairly easily on a GO GAUGE but won't even begin to close on a NOGO GAUGE. Add in the shorter barrel and I figured I'd have to tweak my handload a little. It seems that 75.1gr of VihtaVuori N540 works quite well (see target below). The previous load used 74.2gr of N540. I need to do a little more testing along with some chronograph work to check the velocity (should be around 2,800 fps) but so far I'm pleased with the accuracy. Here are a couple of photos of the finished rifle and a target I shot yesterday morning. I need to be 2.75" 1.8" high at 100 yards for a 200 yard zero so I made a small scope correction after shooting the group shown below.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_dipped_final_01.jpg

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_dipped_final_02.jpg

Here's the target shot yesterday morning. I've found that using the sling and resting my left hand on the rest, in addition to using a properly sized target for the RZ600 reticle, really helps consistency.

http://thr.mcmxi.org/rifles/kimber/talkeetna/load_development/11_08_15/75.1gr_N540_250gr_ttsx_02.jpg

http://thr.mcmxi.org/rifles/kimber/talkeetna/load_development/11_08_15/75.1gr_N540_250gr_ttsx_01.jpg

Robert
November 9, 2015, 02:08 PM
Man that is nice. Now just have to finish my AR10 project and some work on my truck and maybe my 375 can get an overhaul...

MCMXI
November 9, 2015, 05:08 PM
Robert, thanks for the approval. I look forward to seeing your .375 H&H once you've made some changes.

Correction: I need to be 1.8" high at 100 yards and not 2.75" as I mentioned in my previous post. I inadvertently had "Powder Temperature" enabled (value of 40F) in the Applied Ballistics app that I use in my phone which was the outside air temp. I don't know what algorithm AB is using but they sure aren't QuickLOAD so I don't trust that feature. They don't ask for the type of powder so how can they adjust for temperature? Regardless, +1.8" at 100 yards is where I need to be for the RZ600 reticle to work.

Here's one more photo showing how the KUIU Verde pattern seems to "adapt" to its surroundings.

http://thr.mcmxi.org/rifles/kimber/talkeetna/photos/talkeetna_dipped_final_03.jpg

Robert
November 9, 2015, 06:35 PM
Robert, thanks for the approval. I look forward to seeing your .375 H&H once you've made some changes.
Eh, don't hold your breath. I work on a very limited budget. One day...

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