Reloading for 303/375 - p14 Enfield

Thanks for the additional responses fellas.

Andy, I just measured several of the 20 fire formed cases, I can't really load them up as there's some neck tension on some parts of the cases, and none at other parts. they range in neck diameter, but most are between 0.4000 to 0.4050

I guess it's hard to be exact to the thousandth of an inch, as the exact place of measurement on the extension of my micrometer seems to differ as well as the amount of tension I apply with my thumb makes things vary a couple thousandths. Obviously the fourth decimal place is rounded to the nearest 5 or 0.

As far as the highest part of the body, which would help me select a die for an already existing caliber and chopping like you say, I measure about 0.4500 +/- 0.002. The 375hh is 0.4480 through the same place so that should be close enough.

The neck is about 0.3000 in length depending on how far I want to trim it. The 375hh is 0.3520 length at the neck.


From what I see, that 375hh die should be able to work if chopped down. Does that logic seem right?


I picked the 225 grain bullet because I was concerned over velocity and expansion, but I am quite pleased to hear that 270s will be suitable.

By the way Andy, we met several years ago at the EOHC but I don't know if you remember. A mutual friend introduced us, he goes by skscanuck.
 
Archibald said:
Thanks for the additional responses fellas.

Andy, I just measured several of the 20 fire formed cases, I can't really load them up as there's some neck tension on some parts of the cases, and none at other parts. they range in neck diameter, but most are between 0.4000 to 0.4050

I guess it's hard to be exact to the thousandth of an inch, as the exact place of measurement on the extension of my micrometer seems to differ as well as the amount of tension I apply with my thumb makes things vary a couple thousandths. Obviously the fourth decimal place is rounded to the nearest 5 or 0.

As far as the highest part of the body, which would help me select a die for an already existing caliber and chopping like you say, I measure about 0.4500 +/- 0.002. The 375hh is 0.4480 through the same place so that should be close enough.

The neck is about 0.3000 in length depending on how far I want to trim it. The 375hh is 0.3520 length at the neck.


From what I see, that 375hh die should be able to work if chopped down. Does that logic seem right?


I picked the 225 grain bullet because I was concerned over velocity and expansion, but I am quite pleased to hear that 270s will be suitable.

By the way Andy, we met several years ago at the EOHC but I don't know if you remember. A mutual friend introduced us, he goes by skscanuck.
Click to expand...

A 375 H&H die cut down will work if the neck outside diameter, bullet seated with 2-3 thou neck tension is about 0.402"-0.404". If it's a bit smaller, a Lee 0.401" lube-sizer would work. Smaller than 0.400" and you're looking at a drilled bolt. The first thing you need to do is accurately determine that loaded neck outside diameter. You can estimate by measuring the thickness of the brass at the neck with your micrometer, multiplying by two (2), and 0.375" and subtracting 0.002", but a better way is to actually seat a bullet. Try it and if the bullet is gripped well, you can just measure.


Small world, but unfortunately I can't remember you..... :redface:
 
Archibald, you could use a Hornady neck sizer since they are not caliber specific
and have lots of room in the inside for nearly any case and are short enough to work for most requirements.
BB
 
bigbull said:
Archibald, you could use a Hornady neck sizer since they are not caliber specific
and have lots of room in the inside for nearly any case and are short enough to work for most requirements.
BB
Click to expand...

Do they have one for 375? I thought they stopped at 35 cal.
 
I am going to order a full length 375 h&h die and cut it down on the threads, so that I can adjust it to neck size my cases. I will post results in a few weeks once I complete the task.

Also, I am going bison hunting the end if this month, this rifle may make the trip if I can get a hard hitting bullet (225gr or maybe even 270gr) with some good velocity behind it.
 
I forgot to mention, I also picked up another enfield in 303-35 caliber, that one doesn't have iron sights but is drilled and tapped for god knows what scope mounts (the usual for a p14 or model 17 enfield). That's a project for another day. From looking at the chamber it doesn't appear to have much of a pronounced shoulder, and is more tapered like the original 303 Brit, without the body blown out like this 303-375. I am beginning to get excited about what this cartridge and rifle can do, I will let you guys know what velocities I get.
 
Archibald said:
I am going to order a full length 375 h&h die and cut it down on the threads, so that I can adjust it to neck size my cases. I will post results in a few weeks once I complete the task.

Also, I am going bison hunting the end if this month, this rifle may make the trip if I can get a hard hitting bullet (225gr or maybe even 270gr) with some good velocity behind it.
Click to expand...

Archibald,

Klondike Bob on this site lives in Whitehorse, and has barrelled up a few 375-303 rifles over the years. He also makes the dies, and might have a set on hand. For sure, he can make you a stubby die to neck size in about twenty minutes.

Ted
 
Hi Archibald I just came across this post.
Your cartridge looks very similar to mine.
It's a blown out 303 necked up to. 375
Called the 375 Jennings the gunsmith who made it. Mine is in a LE NO.5 action I have worked up loads using 9.5x56 data. So far have only gone up to 44 gr. 3031 with a 260gr.
Still no pressure signs. And pretty mild shooting. Just my 2 cents
 

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cross-sticks said:
Hi Archibald I just came across this post.
Your cartridge looks very similar to mine.
It's a blown out 303 necked up to. 375
Called the 375 Jennings the gunsmith who made it. Mine is in a LE NO.5 action I have worked up loads using 9.5x56 data. So far have only gone up to 44 gr. 3031 with a 260gr.
Still no pressure signs. And pretty mild shooting. Just my 2 cents
Click to expand...
What's the brass length on that round you made?

It's been awhile since I responded to this thread (11 years).

I did get this rifle shooting by chopping a few threads off of a 375 h&h die and neck sizing the case.

I just haven't messed with that rifle much since then. I should probably cerakote or parkerize the rifle and put it into a decent stock with a scope and put it to good use.
 
Archibald said:
What's the brass length on that round you made?

It's been awhile since I responded to this thread (11 years).

I did get this rifle shooting by chopping a few threads off of a 375 h&h die and neck sizing the case.

I just haven't messed with that rifle much since then. I should probably cerakote or parkerize the rifle and put it into a decent stock with a scope and put it to good use.
Click to expand...
To be honest I have never checked it after fire forming the case. It's just a standard 303 blown out straight and then necked to. 375
It was a Canadian gunsmith here in B.C. who made it I was just lucky enough to get one.
I think he only made about a dozen.
 
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