Sizing down 375 h&h to 300 h&h... possible?

Majo

New member
Joined
Dec 6, 2020
Messages
5
Reaction score
7
Hi there!

Long time reader, first time posting...

First of all, nice to be here and thanks in advance.

Question is easy... could I size 375 h&h (i have a bunch of once-fired cases) to 300h&h? I’m waiting to get a new (to me) sako finnbear... brass is expensive and hard to find, so will be nice to have a backup plan...

By the way, any feedback on the 300 holland will be nice. I’m considering to load sierra 165 game king hpbt (#2140) at mild velocities... but may be better to step up to 180-200 grains... I don’t care about recoil, but don’t need too much bullet for reds and boars in Spain... not planing to go to Africa yet

Thanks!!
 

GuttormG

AH enthusiast
Joined
Mar 27, 2016
Messages
351
Reaction score
369
Media
8
Yes, it can be done. Annealing the case, good lube and maybe in several steps.
RCBS has/had a forming die to do this.
Propably much easier to make from 7mm Rem.mag or 300 win mag
 

sierraone

Silver supporter
AH legend
Joined
Oct 14, 2013
Messages
3,852
Reaction score
3,681
Media
91
Articles
1
Hunting reports
Africa
2
Member of
Dallas Safari Club, Safari Club Int.
Hunted
USA, RSA, Northwest and Limpopo Provinces
There you go....someone on this forum always has the answer. But you suggested it yourself, if you do go to Africa with it to hunt, go with the heavier bullets for that caliber. The smallest caliber I have hunted with in Africa was a .375 HH, although I do own a .300 HH but only shoot it locally. Dead accurate but I shoot factory 180 grain ammo. Congratulations and good luck!

And welcome to our forum!
 

fourfive8

AH elite
Joined
Apr 27, 2017
Messages
1,643
Reaction score
2,631
Media
229
Hunted
USA, South Africa, Mozambique, Zimbabwe, Zambia, Botswana
You'll need to start close to the 300 HH length of 2.850". Otherwise you'll end up with cases that are too short. 375 HH and 8 MM Remington Mag are two of the standard belted mag lengths that are 2.850". Another potential problem to consider is that reducing the caliber increases neck wall thickness. May or may not be an issue. Best bet is to use 300 HH brass from the beginning.

Here in the US at least it is available but you have to look around. Gunbroker sources average $50-75 per 20 or less if once fired. The Redding 300 HH Form and Trim die is about $50. I have no idea of availability for any reloading tools or components in Europe. New PRVI/PPU 300 HH brass is available here so would be one possible European source.
 

TOBY458

AH legend
Joined
Jan 23, 2014
Messages
2,341
Reaction score
4,458
Location
Madison Georgia, USA
Media
182
Articles
2
Hunting reports
Africa
3
Yes, it can be done. Annealing the case, good lube and maybe in several steps.
RCBS has/had a forming die to do this.
Propably much easier to make from 7mm Rem.mag or 300 win mag
7mm Rem Mag and 300 Win Mag are a shortened version of the H&H case. So he unfortunately wouldn't be able to make the longer 2.85" case for 300 H&H from these two calibers.
 

Majo

New member
Joined
Dec 6, 2020
Messages
5
Reaction score
7
Thank you for the replies.

300wm/7rm will not work.

300wby may work... but I just have 150-200 pcs 375 h&h that could use if this work ok.

I like to use good quality brass... so will probably go with norma 300 h&h brass. I can source them in Germany for 88€ (105 usd) for 50 pcs. Not cheap but they should last me (unfortunately LOL) a couple years...

Keep the good info in the “30super” coming!

Cheers
 

TOBY458

AH legend
Joined
Jan 23, 2014
Messages
2,341
Reaction score
4,458
Location
Madison Georgia, USA
Media
182
Articles
2
Hunting reports
Africa
3
Case length, forgot that!
300 weatherby will work, a rad shorter but it doesn't really matter (0,6m)
I just wonder if the sharp shoulder of the 300 WBY would be easy to remove? That sloping shoulder on the H&H is definitely much less defined than what the WBY has. Would be interesting to try.
 

wswolf

AH member
Joined
Jul 7, 2017
Messages
32
Reaction score
24
Location
Montana
Member of
NRA, Western Montana Fish & Game Association
Hunted
Zimbabwe
Hi there!

Long time reader, first time posting...

First of all, nice to be here and thanks in advance.

Question is easy... could I size 375 h&h (i have a bunch of once-fired cases) to 300h&h? I’m waiting to get a new (to me) sako finnbear... brass is expensive and hard to find, so will be nice to have a backup plan...

By the way, any feedback on the 300 holland will be nice. I’m considering to load sierra 165 game king hpbt (#2140) at mild velocities... but may be better to step up to 180-200 grains... I don’t care about recoil, but don’t need too much bullet for reds and boars in Spain... not planing to go to Africa yet

Thanks!!
I just tried sizing a .375 H&H case, which has been fired several times, in a .300 H&H die. A normal amount of lubricant was applied by rolling the case on a case-lube pad.. The sizing did not require great effort and the case formed perfectly. The length of the case increased by .025".

My favorite loads include 180 Nosler Partitions with H4350, H4831, Reloder 23, or Reloder 26 and 200 Partitions with Reloder 23, Reloder 26 or Ramshot Magnum.

Cheers
 

Majo

New member
Joined
Dec 6, 2020
Messages
5
Reaction score
7
I just tried sizing a .375 H&H case, which has been fired several times, in a .300 H&H die. A normal amount of lubricant was applied by rolling the case on a case-lube pad.. The sizing did not require great effort and the case formed perfectly. The length of the case increased by .025".

My favorite loads include 180 Nosler Partitions with H4350, H4831, Reloder 23, or Reloder 26 and 200 Partitions with Reloder 23, Reloder 26 or Ramshot Magnum.

Cheers
Thanks for the info! Good news, then...

I’m worryed about neck thickness when sizing down from .375... may need turning...

Planning to load sierra prohunter RN 180 and the Gameking HPBT 165 too... over N160/N560 btw...
 

Newby

AH veteran
Joined
Oct 22, 2019
Messages
133
Reaction score
242
Location
Australia
Hunted
Australia, New Zealand, North America, UK, Central Asia
Necking down should lengthen the cases a little, not shorten them.

Neck wall thickness may be an issue, and should definitely be checked; but the only way to check this is to take some measurements before necking down, and again after necking down. Outside neck turning would sort that out if the necks end up too thick.
 

Majo

New member
Joined
Dec 6, 2020
Messages
5
Reaction score
7
Necking down should lengthen the cases a little, not shorten them.

Trimming is not an issue... quick and easy.

But I was referring to turning the necks... let´s see if WSWOLF came by again and share some more feedback with us!
 

fourfive8

AH elite
Joined
Apr 27, 2017
Messages
1,643
Reaction score
2,631
Media
229
Hunted
USA, South Africa, Mozambique, Zimbabwe, Zambia, Botswana
If all else goes well with sizing down... neck wall thickness can be checked with a ball mic. and that number can be compared to regular, new factory brass. The critical thing, however is that the loaded round have enough clearance between the neck and chamber wall for "easy" bullet release upon firing. Most consider .002-.003" to be OK but marginal with .004"-.008" in the range of average or normal for chambers designed for reliable hunting or tactical applications. Too little can drastically increase pressure. It only takes one out of a batch!! and not all brass thicknesses are uniformly equal within a batch. Also, any excessive sizing will work harden the brass in the neck and can shorten useful life of the case.

An easy check for chamber neck clearance-- Measure the neck diameter of a fired round, preferably one that has been fired a few times and/or with a full pressure load. Add .001" for brass shrink back after firing- that is about the diameter of the rifle's chamber neck. Compare that number to a loaded round. That difference will be an approximation of total clearance.

Of course you can anneal the neck and shoulder prior to sizing down to help in the sizing operation and to delay the effects of work hardening. If after reforming you find the neck wall thickness is too great, the necks can be turned down. Neck turning is not difficult but requires another couple of tools. It is tedious to do correctly, is time consuming and one of my least favorite case prep operations.
 

wswolf

AH member
Joined
Jul 7, 2017
Messages
32
Reaction score
24
Location
Montana
Member of
NRA, Western Montana Fish & Game Association
Hunted
Zimbabwe
Using a RCBS Case Master tool I got the following neck thickness measurements:
New Hornady .300 H&H - .012 to .013"
New Norma .300 H&H - .012"
Winchester .300 H&H formed from .375 H&H - .013 to .014"

Probably not a problem unless you have a particularly tight chamber.

fourfive8 wrote a post worth remembering!
 

Arzie

New member
Joined
Oct 9, 2020
Messages
3
Reaction score
7
Location
SE Washington
Member of
NRA Life Member
Hunted
Washington, Idaho
Well I have about a 150 rounds of .300 H&H brass that I want to get rid of and need some .375 H&H brass.
 
Joined
Oct 28, 2018
Messages
3,343
Reaction score
5,127
Location
Wyong new south Wales Australia
Media
8
Hunting reports
Africa
1
Member of
SSAA
Hunted
Australia
Yes, it can be done. Annealing the case, good lube and maybe in several steps.
RCBS has/had a forming die to do this.
Propably much easier to make from 7mm Rem.mag or 300 win mag
@ GuttormG
The 7mm and 300 are to short to form into 300 H&H.
You should be able to neck the 375 down to 300 in one pass on a good press. Keep a close eye on neck thickness but this can be easily fixed by dreaming or neck turning if needed.
Bob
 
Joined
Oct 28, 2018
Messages
3,343
Reaction score
5,127
Location
Wyong new south Wales Australia
Media
8
Hunting reports
Africa
1
Member of
SSAA
Hunted
Australia
I just wonder if the sharp shoulder of the 300 WBY would be easy to remove? That sloping shoulder on the H&H is definitely much less defined than what the WBY has. Would be interesting to try.
@TOBY458
I've tried necking down a 35 Whelen AI to standard Whelen with no success due to the shoulder. It came close but no cigar.
Bob
 

tarbe

AH legend
Joined
Jan 26, 2014
Messages
4,195
Reaction score
7,048
Location
Cypress, TX and Romance, MO
Media
120
Articles
1
Hunting reports
Africa
1
Member of
NRA Life, Handloaders Anonymous
Hunted
USA, South Africa, Zimbabwe
Smart move to keep the Sierras at mild velocities. :) 308 level should be ok for the most part.
 

Forum statistics

Threads
36,641
Messages
694,174
Members
64,166
Latest member
fireman
 

 

 

Latest posts

Latest profile posts

Rifle57 wrote on Rimshot's profile.
I bought some bullets from Rimshot and he is good to trade with!
Greetings all! I've been a hunter for 50 years, but only now planning a trip to Africa. I was fortunate and successfully bid on a couple hunts for plains game in SA later this year and next. Also a rare Native Texas (5th generation) and USMC Vet. Hunt safe y'all!
uujm wrote on trg's profile.
I am looking for a Safari Express. Was yours made in New Haven or South Carolina? Any other details you can give me? I am very motivated to buy.
pimes wrote on flatwater bill's profile.
Hello Bill - can you tell me that landowner/ranch/outfitter - Thank you!
Pete0905 wrote on damundsen87's profile.
Hello
Is the Khales 1-6 still for sale?
Thanks
Josh
 
Top