.375 IMR4350 & 300gr Barnes TSX

HenryB

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I need a accurate formula for the following on reloading:

  • Winchester Model 70 .375 (NEW)
  • Powder - IMR4350
  • Primer - CCi250
  • Bullets - 300gr Barnes TSX

Who can help me with the correct loading info & Bullet Length?
 

fourfive8

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I need a accurate formula for the following on reloading:

  • Winchester Model 70 .375 (NEW)
  • Powder - IMR4350
  • Primer - CCi250
  • Bullets - 300gr Barnes TSX

Who can help me with the correct loading info & Bullet Length?
You can go to both the Hodgdon data site and the Barnes data sites and find useful info. Hodgdon site lists an IMR 4350 load for 375 HH, 300 gr.

Begin at suggested starting load for 300 gr bullet and use a chronograph to work up loads. Here's a link to Hodgdon data for 375 HH IMR4350 and 300 gr. https://www.hodgdonreloading.com/reloading-data-center

Bullet should be seated where case mouth rim at (in) top groove in TSX bullet.

Hit Rifle tab, select 375 HH, select 300, select IMR, select 4350, select Update Data- load should pop up. Use this data as a guide for loading TSX bullet. Start at suggested starting and work up. TSX bullets usually like a little jump to lands, so seating bullet to where mouth rim is at or crimped into top groove usually provides some jump in most standard chambers. Factory chamber in Win 70 should be fairly close to standard.
 
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HenryB

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Thank you for the info.
You can go to both the Hodgdon data site and the Barnes data sites and find useful info. Hodgdon site lists an IMR 4350 load for 375 HH, 300 gr.

Begin at suggested starting load for 300 gr bullet and use a chronograph to work up loads. Here's a link to Hodgdon data for 375 HH IMR4350 and 300 gr. https://www.hodgdonreloading.com/reloading-data-center

Bullet should be seated where case mouth rim at (in) top groove in TSX bullet.

Hit Rifle tab, select 375 HH, select 300, select IMR, select 4350, select Update Data- load should pop up. Use this data as a guide for loading TSX bullet. Start at suggested starting and work up. TSX bullets usually like a little jump to lands, so seating bullet to where mouth rim is at or crimped into top groove usually provides some jump in most standard chambers. Factory chamber in Win 70 should be fairly close to standard.
Thank you will go through these links.
Looking for specific info on someone who has done it before with the same recipes I have. Trying to buy some time getting this in tune with the rifle.
 

PARA45

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@HenryB, unfortunately what worked for someone on their rifle, may not work on your rifle, way too many variables. We normally do not share what works for us, because the load that is safe in our rifle, may not be safe in yours. Use the data available from Hodgdon, or Barnes, and let your rifle tell you what she likes and go from there.
 

Surgeon1

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I use IMR 4350 at 75.5gr with 300gr A-Frame and get amazing accuracy in 3 different 375's
Barnes accuracy has never equaled A-frames in virtually every big caliber I've tried it in.
Barnes need to be at least .050 off the lands. I have one 375 that will shoot TSX 300 with H4895 and 67.5 gr into 0.95 CTC 3 shot, same gun with A-frames shoots 0.43 CTC all 3 touching
 

HenryB

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@HenryB, unfortunately what worked for someone on their rifle, may not work on your rifle, way too many variables. We normally do not share what works for us, because the load that is safe in our rifle, may not be safe in yours. Use the data available from Hodgdon, or Barnes, and let your rifle tell you what she likes and go from there.
Yes agree with this 100%. Thank you
 

HenryB

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I use IMR 4350 at 75.5gr with 300gr A-Frame and get amazing accuracy in 3 different 375's
Barnes accuracy has never equaled A-frames in virtually every big caliber I've tried it in.
Barnes need to be at least .050 off the lands. I have one 375 that will shoot TSX 300 with H4895 and 67.5 gr into 0.95 CTC 3 shot, same gun with A-frames shoots 0.43 CTC all 3 touching
Thank you for the info, very interesting. What is your total bullet length for your load
 

C.W. Richter

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COAL depends upon your rifle chamber specifics, but you can start with standard COAL and give that a whirl, as you WILL be using std COAL factory ammo when the baggage handlers lose your ammo, not to mention sticky, tight (i.e. neck-sized only, bullet touching lands) cartridges in hot weather can kill a friendship! ;)
300 Winchester
IMR-4350​
78.0C​
2,620​
4,574​
25.0​
350 Woodleigh
IMR-4350​
75.0M​
2,405​
4,497​
23.0​
If you're hunting DG, consider the 350 grainers instead of the 300s. ;) Nos PTs are even more accurate than the Swifts (better bc/shape), but they aren't as deadly on DG. Most .375 bullets are in the 1.5" long range. :p The cartridge is 3.600" in std form. Not all chambers are the same specs (for greatest accuracy, it's very gun specific.) Interesting...I see you've joined to get free reloading info, as opposed to joining a reloading site! :p Good luck. As with any reloading data and varying rifle construction/quality/age, consider reducing those max loads and testing first. In reality, even a 375HH that shoots 2" groups using factory ammo will get the job done well at the range it was intended for on DG. 6" @ 300 yds for PG will still get the job done.
 
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HenryB

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Thank you for your details response. Would you be able to point me to the relaoding sites, also discussion sites?
new in this and learning allot.
 

Shootist43

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HenryB, I've been reloading for 40 years and from experience can tell you that you've been given some very sound advice. Please don't try to short change the "process." I own three 375 H&H rifles and they don't like the same ammunition. Without a doubt all of them will hunt, but I'm forever looking for the smallest group at the highest velocity. Let us know how you make out. A book that I thought was "a cut above" is titled The Practical Guide to Reloading written by Nathan Foster. Following is a link to his website: https://www.ballisticstudies.com/shop/The+Practical+Guide+to+Reloading.html
 

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PARA45

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@Shootist43, thank you sir for the info on the book, I’ve been reloading for 40+ years as well, and I’m always looking on how to improve on my reloading skills and to learn more. Can never have too much knowledge. Thank you sir. (y)
This why I love this site.
 

machinistbutler

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I have loaded for a few 375 H&H , with a few different 300 grain bullets, but not the tsx


All seemed to shoot great with 75 grains of IMR 4350. IMR 4831 too slow..


RL 15 worked awesome with lighter weight bullets including a tsx.
 

PHOENIX PHIL

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I need a accurate formula for the following on reloading:

  • Winchester Model 70 .375 (NEW)
  • Powder - IMR4350
  • Primer - CCi250
  • Bullets - 300gr Barnes TSX

Who can help me with the correct loading info & Bullet Length?

You've received some good advice, here's a few more things to think about:

1) The Barnes all copper bullets need a clean barrel, I mean really clean. Thoroughly clean that barrel and ensure any lead and previous copper from shooting other bullets is removed. If you don't do this, you risk chasing your tail and wasting time and money.

2) My M70 loves IMR4350 with a number of bullets and so I think you're on the right track with this powder.

3) At the risk of being chastised by some Barnes fans on AH, in my opinion and from experience you need to be aware of copper build up from the TSX. My experience and also that of others has been that when enough copper builds up in the barrel, accuracy will suddenly drop off and quite severely. Now this doesn't happen to everyone, but it does for some of us. So as your shooting, every few shots take a look at the crown of your barrel and pay attention to the lands you can see. Monitor this as I say. If you have this problem, it'll be evident. After some number of shots for me, those lands look like the copper of a nice new shiny penny. If you experience the sudden drop off in accuracy, go back and clean that barrel before you send anymore rounds down the barrel. If this was the problem, accuracy will return. Again this may not be a problem for you, but it's something to keep in mind so you don't start chasing rabbits.
 

meigsbucks

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My .375 gave its best accuracy with the 300 gr Barnes TSX, but using 748 powder. IMR 4350 never gave me the accuracy or velocity I was looking for with any 300 gr bullet. I’ve also found H4895 works well.
 

Shootist43

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Para45, as far as I'm concerned Nathan's book belongs on the shelf of every reloader. I bought the hard cover as well as the E- Book.
 

PARA45

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Para45, as far as I'm concerned Nathan's book belongs on the shelf of every reloader. I bought the hard cover as well as the E- Book.

After looking and reading about it, you are 100% correct sir, and this is why I'm getting it. :) When it comes to reloading, I believe we never stop learning. Good call on posting this book here. (y) (y)

My apologies to the OP, for derailing the post a bit.
 

C.W. Richter

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You've received some good advice, here's a few more things to think about:

1) The Barnes all copper bullets need a clean barrel, I mean really clean. Thoroughly clean that barrel and ensure any lead and previous copper from shooting other bullets is removed. If you don't do this, you risk chasing your tail and wasting time and money.

2) My M70 loves IMR4350 with a number of bullets and so I think you're on the right track with this powder.

3) At the risk of being chastised by some Barnes fans on AH, in my opinion and from experience you need to be aware of copper build up from the TSX. My experience and also that of others has been that when enough copper builds up in the barrel, accuracy will suddenly drop off and quite severely. Now this doesn't happen to everyone, but it does for some of us. So as your shooting, every few shots take a look at the crown of your barrel and pay attention to the lands you can see. Monitor this as I say. If you have this problem, it'll be evident. After some number of shots for me, those lands look like the copper of a nice new shiny penny. If you experience the sudden drop off in accuracy, go back and clean that barrel before you send anymore rounds down the barrel. If this was the problem, accuracy will return. Again this may not be a problem for you, but it's something to keep in mind so you don't start chasing rabbits.
If it weren't an issue Barnes wouldn't make that special cleaner to remove the copper and the molybdenum prior on coated bullets. I've strayed away from Barnes on most applications excepting some very large case long range magnums (MRX, LRX) simply because a bullet constructed of a less dense metal results in a longer bullet that eats up valuable powder capacity.
 

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