adjusting listed powder charge for lighter bullet

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kealil

New member
Hello All!

I have a quick question: What is the best way to find starting loads for a bullet weight that is not listed in a manual? I am starting to reload for my new Enfield and have found that my bore slugs to .311. I have a mold that drops a gas checked bullet to the proper size but is a full 35 grains lighter than the lightest bullets in any of my manuals. I've never messed with a weight difference of this size in experience. Can I just adjust the charge by the same proportions for a bullet of the same type and profile as a starting place?

Example:
Bullet from mould drops at 150gn including GC
Lightest bullet of same type in manuals:185gn
Suggested starting powder charge for 185gn IMR 4227: 20gn
150/185 = 81%
.81*20 = 16.2

could I use 16.2gn as a starting load for this bullet?

I just want to check my reasoning since my manual doesn't cover this topic. Am I on the right track?

Thank you all!
 
My old (really old) Lyman 42nd edition manual came up with the following powder choices.
2400
4227
4831
H380
Hi-Vel
4895 (doesn't specify IMR or H)
3031
4350
&
Unique.

Here's the rub, although 4227 is in the "standard" list of powders they use for many things there are no listings at all for it in the .303 Brit case. That probably means there was some mis-match between the powder & the .303 round.:o

I have .303/150 gr cast data for:
2400
H380
Hi-Vel (if its still made?)
4895
3031
&
4350

Do you have/can you use any of those powders?
 
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QL tells me for 24" barrel 30-06, seated at 3.00":

● 180gr cast/IMR4227/26.0gr/24,545psi/1,857fps (about optimal pressure for Lyman#2)

● 152gr cast/IMR4227/28.0gr/24,607psi/2,032fps

YMMV of course, but this gets you into the ballpark and is
"not inconsistent" w/ CE Harris' article in the above cite.

What bullet are you [the OP] actually casting ?
BTW: See Lyman's Cast Bullet Hndbk for multiple bullet weights using 4227.
All are in the range above.
 
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Since you are using cast bullets dropping from the mold at .311, I am assuming that the rifle is perhaps an '06 1917 Enfield (that "new" means new to you), as opposed to a .303 Lee Enfield that uses cast bullets sized to around .313. If we are talking '06, the Lyman 49th Edition only shows one cast bullet '06 load using 4227 powder and this is for a 200 gr bullet. With the 200, loads of 21 through 29 grains 4227 show 19,100 to 35,400 PSI, so anywhere in that range I would think would be a safe starting load for the much lighter 150 (I would start near the upper end). More precise data based on loads for the 160 gr cast bullet could be given if using such powders as Unique, 4198, 3031 or Trail Boss. If the rifle is a Lee Enfield, the Lyman 49th shows 20 thru 26.5 grains 4227, again for a 200 grain cast bullet with pressures not given.
 
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We know you want to use IMR4227 powder and a 150 grain cast bullet.
I'm still unsure if you are referring to 30-06 or 303 British.
The make/ mould number of the bullet you will be using will also be helpful.
Details like this matter a lot.
I have a lot of manuals covering cast bullets and can probably find the information you need.
Load safe, Gary
 
Mehavey,

If he's shooting a .311" bore Enfield, I'd assume it's .303 British, but he can fill us in if I am guessing incorrectly that. Unfortunately it does seem to be omitted from a lot of manuals.


kealil,

Unfortunately, as other stated, it's not a linear proposition, so simple interpolation won't get you there. The actual numbers are affected both by the bullet weight and the difference its length and seating depth make to the amount of space the powder starts burning in, and also how far it jumps from the case to the lands, as that affects how much gas bypasses the bullet before it obturates the bore and pressure starts to build in earnest. The QuickLOAD software is the best means of estimating, assuming it correctly predicts the known loads. You sometimes have to tweak its burn rates and almost always have to tweak its case capacity numbers to get there.

In this case, however, you are using light loads at modest velocities that will be well below jacketed bullet pressures, so small errors don't have a lot of consequence.

Otherwise, there a couple of things you can always shoot, even if they are mild. One is Rocky Raab's universal 30 caliber load of 9 grains of Unique. This is the sort of load a kid will like shooting because it is so mild.

Another is a Trail Boss load. You can, according to Hodgdon, occupy anything from 70% to 100% (but no compressed loads) of the space under the bullet with Trail Boss, and it will be safe. A 13 grain load should produce about 1400 fps in the long barrel Enfield (30.2"), and about 25 fps less in the SMLE.
 
OK......
Running a 303Brit w/ an OAL of 3.075" which is probably long), and diameter adjusted to 0.311"

● 180gr/IMR4227/24.6gr/24,294psi/1,835fps (optimal Lyman#2 pressure)

● 150gr/IMR4227/26.6gr/24,350psi/2,011fps

Again... ballpark YMMV
 
Oops, misread .311 as bullet diameter as dropped from mold rather than slugged bore diameter. So all bets are off regarding caliber that I took to be an '06. Probably now a .303.
 
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Hello all thank you for the clarification.

It is for a 303 British Enfield.

The specific mould is the LEE C312-155-2R.

It is the same mould that I was planning to use for my 7.62x39 SKS. That particular project never occurred for other reasons but I wanted to try lighter bullets since I already have a nice stock of them.
 
"...could I use 16.2gn as..." No. Way under minimum for a cast 150.
Use 25.0 to 28.0. Data's out of my old 45th Edition Lyman book.
 
I looked at Lyman #46 and found a 151 grain cast bullet (close enough; their mold #311466) listed for .303 British. Interestingly, it lists only fast powders in that edition under that lead bullet, with the Unique I suggested earlier being the best performer of the lot. They must have discontinued the mold before my current 49th edition and the new Cast Bullet Handbook came out.

For Unique they list 11 grains to start and 15 maximum. This gives 1475 to 1760 fps from their 25" SMLE barrel. The other powders all max out at lower velocity, but I know you can shoot cast bullets with Unique at least down to 8 grains in .30-06, so it should do that just fine in the .303 British, too.
 
QL:
303Brit/152gr/Unique/12.5gr/24,122psi/1,687fps (ideal Lyman#2 pressure

Right in line w/ UncleNick above.
Go with either the Unique or the IMR4227 [listed prior] option
 
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Thank you again for all the info!

Unclenick, your post reminded me that I have a stash of old reloading manuals that I digitized a few years ago. I never needed them before now but lo and behold in my Lyman 44th edition:
mt0C8201.png


That old manual pretty much confirms what you guys have been telling me. It even has a mention the loads of Unique. I would switch to Unique if I could get ahold of a decent amount. I haven't seen Unique in the wild for years but 4227 is on most shelves now.

Thanks again all, I have somewhere to start now:D
 

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