200 gr 303 Brit

I'd recommend buying the Lyman Cast Bullet Handbook. It's only $30-40 and has a lot of information other than load data.
Unfortunately there isn't any data for either of the 4895's in it.

My go-to powders for cast bullets in most cartridges including 303B are either of the 4198's, Trail Boss, SR-4759 (discontinued), or Unique.
 
H4198 and Trail Boss are plentiful around here. Discontinued and Alliant powders are practically non-existent, I know.
The Lyman book might not have it because they couldn't get it to work well.
Personally I've never gotten H or IMR 4895 to work well with cast bullets except really heavy big bore stuff like 500gr cast in a 45-70. With most bottleneck cartridges either the velocity is too high and I get leading and no accuracy or the powder doesn't burn fully so I get really inconsistent results. If you went with an extra hard bullet (20-25+ bhn maybe?) it might work with a really smooth, crisp rifling but I'd say there's still a good chance of leading.
 
hodgdon lists a max load of 41gr for a 180gr bullet for IMR 4895 in the 303 british.

i would start the load at 35gr or 36gr with a 200gr bullet and work up from there.
 
LUTNIT said:
H4198 and Trail Boss are plentiful around here. Discontinued and Alliant powders are practically non-existent, I know.
The Lyman book might not have it because they couldn't get it to work well.
Personally I've never gotten H or IMR 4895 to work well with cast bullets except really heavy big bore stuff like 500gr cast in a 45-70. With most bottleneck cartridges either the velocity is too high and I get leading and no accuracy or the powder doesn't burn fully so I get really inconsistent results. If you went with an extra hard bullet (20-25+ bhn maybe?) it might work with a really smooth, crisp rifling but I'd say there's still a good chance of leading.
Click to expand...

Your experience is about the opposite of mine. I use IMR4895 in several different rifles with velocity up to 2000 fps with no leading. Those cartridges include 9.3x57, .308, 303 and 30-06 using cast bullets. I've also found that cast bullets that are too hard tend to cause more leading issues rather than less.
 
jethunter said:
Your experience is about the opposite of mine. I use IMR4895 in several different rifles with velocity up to 2000 fps with no leading. Those cartridges include 9.3x57, .308, 303 and 30-06 using cast bullets. I've also found that cast bullets that are too hard tend to cause more leading issues rather than less.
Click to expand...
Most of my cast bullet shooting is in surplus rifles with somewhat rough to downright horrible bores so maybe that is why. According to my records I loaded some 300WM with cast bullets and H4895 for my Rem 700 but I can't find the records of when I shot them. Maybe they're sitting in an ammo box somewhere still.

-----------------------------

I did some digging and most people say the 60% rule works with IMR4895.
For the H4895 and 60% rule see here: http://www.imrpowder.com/PDF/Youth Loads.pdf
Now the question is, is it safe to use data for a 180gr bullet and swap to a 200gr bullet if you reduce the charge to 60% of the listed max?

60% of 41.0gr is 24.6gr. That sounds reasonable to me. I would probably start at maybe 25gr and work up but hold no liability if it explodes.

----------------------------

Woodleigh sells 215gr .312" RN bullets and have load data on their site. There is no 4895 listed but they do list a load with varget. It's 36 to 39.5gr with velocities of 2130 to 2265. With H4350 they list 42-45gr and 2045 to 2185fps.

303british.com also has loads for 215gr RN bullets but still no 4895. Their loads use H4350, H4831, and Reloader19. Lower maximum velocities at around 2100fps at max.

So if you want to try to develop a load for a 200gr cast bullet with IMR4895 you could try the 60% rule with 180gr data, chrony the rounds as you work up, and know you have a ceiling of around 2200fps though I'd stop at around 2000-2100fps. Chances are you'll run into accuracy issues when you start to approach 2000fps so it may be moot.
 
LUTNIT said:
Most of my cast bullet shooting is in surplus rifles with somewhat rough to downright horrible bores so maybe that is why. According to my records I loaded some 300WM with cast bullets and H4895 for my Rem 700 but I can't find the records of when I shot them. Maybe they're sitting in an ammo box somewhere still.

-----------------------------

I did some digging and most people say the 60% rule works with IMR4895.
For the H4895 and 60% rule see here: http://www.imrpowder.com/PDF/Youth Loads.pdf
Now the question is, is it safe to use data for a 180gr bullet and swap to a 200gr bullet if you reduce the charge to 60% of the listed max?

60% of 41.0gr is 24.6gr. That sounds reasonable to me. I would probably start at maybe 25gr and work up but hold no liability if it explodes.

----------------------------

Woodleigh sells 215gr .312" RN bullets and have load data on their site. There is no 4895 listed but they do list a load with varget. It's 36 to 39.5gr with velocities of 2130 to 2265. With H4350 they list 42-45gr and 2045 to 2185fps.

303british.com also has loads for 215gr RN bullets but still no 4895. Their loads use H4350, H4831, and Reloader19. Lower maximum velocities at around 2100fps at max.

So if you want to try to develop a load for a 200gr cast bullet with IMR4895 you could try the 60% rule with 180gr data, chrony the rounds as you work up, and know you have a ceiling of around 2200fps though I'd stop at around 2000-2100fps. Chances are you'll run into accuracy issues when you start to approach 2000fps so it may be moot.
Click to expand...


I just use the Quickload program to determine a starting point when there is no published data available. Then I confirm it with the chronograph.
 
Last edited:
I shoot 185 grain GC in my 303's with 40 grains of IMR 4895. Around 2100 fps with around 2" accuracy.

I can go a bit faster, but I like to load cast for about 3 rifles, so I backed off a little, to save load development for each rifle.

I'd say 37 grains would be good for 200 grainers, most likely...
 
Quickload estimates for a 200 gr bullet in .303 british:

32 gr IMR4895: 1900 fps, 24K psi, 68% case fill
34 gr IMR4895: 2000 fps, 28k psi, 72% case fill
36 gr IMR4895: 2115 fps, 31K psi, 76% case fill
(Max pressure for 303 British is about 53,000 psi.)

Quickload estimates are "ballpark". It's close enough to determine a starting point, and then you can confirm the results with your chronograph. If the chrony reading is close to the Quickload velocity estimate, it gives you some level of comfort with the Quickload pressure estimate at the same time.
 
No cast data on Hodgdon's site. Steve at .303British.com suggests 35.5 for a cast 180 with IMR4895.
This is for a 205 grain Cast with gas check out of my old Lyman book. No IMR4895 though.
Powder Start Vel Max Vel
Unique 10.0 1510 14.0 1600
2400 19.0 1628 24.0 1893
IMR4227 23.0 1745 27.0 1953
Accuracy Load: IMR4227 23.0 12745 fps.
 
You must log in or register to reply here.
Back
Top Bottom