Yes, please post the print. The more eyes the better to make sure it is done right the first time like Oscar said.

Getting close guys!!!!
Wooohooo!!

Capoward,

Please do post the print, as of yet I do not know how to do so. And thanks for the assistance.

Boom, I can not be sure if I will be available for a conference call this week but if any of you Gentlemen would like to contact Mr. Kiff at anytime I'm sure it would be helpful. Oscar

Ok here’s the print:

Edit Added: OK, explanation of reamer print is obviously needed, so here goes:
1) The distance between the “BOLT FACE” and the “DATUM” line in the chamber print equates the cartridge “bolt face/rim interface” to the “belt/case body junction” distance. The chamber print calls for 0.2201” in length for this dimension.
2) The chamber length Neck Chamfer is 2.8701” in length. The chamber print articulates this length by noting the “BOLT FACE” to the “DATUM” line length of 0.2201” plus the “DATUM” line to the “Neck Chamfer” length of 2.6500” for a total of 2.8701” in length.

Edit: Ok print corrected plus additional data added.

Do we need two reamer prints for rough and finish?
It looks like on the print that this is too short.
The case needs to be 2.85" length.
Also the neck area needs to be "Parallel sided" till it wont expand anymore when a sized case is expanded by a 404 expander.

Correct me if I am wrong...


The taper should go to 2.4" from the base of case then parallel sided measuring about .450" for .45" in neck area length. The taper of the 375 is 30 thou total per inch so if a fired case to release the bullet needs to expand say 7 thou then the fired case and reamer needs to be .25" longer of parallel sided or nominal 375 taper to 2.15" @ .457" in diameter. This and the fired 375 case in the body measures about 4 thou larger than an unfired sized once fired case right?

Things to get right...

quote:

Originally posted by boom stick:
Do we need two reamer prints for rough and finish?
It looks like on the print that this is too short.
The case needs to be 2.85" length.
Also the neck area needs to be "Parallel sided" till it wont expand anymore when a sized case is expanded by a 404 expander.

Correct me if I am wrong...


The taper should go to 2.4" from the base of case then parallel sided measuring about .450" for .45" in neck area length. The taper of the 375 is 30 thou total per inch so if a fired case to release the bullet needs to expand say 7 thou then the fired case and reamer needs to be .25" longer of parallel sided or nominal 375 taper to 2.15" @ .457" in diameter. This and the fired 375 case in the body measures about 5 thou larger than an unfired sized once fired case right?

Things to get right...

Boom,

Finish reamer – definitely and have it TIN coated.
Rough reamer - ???... Any re-bored 375 H&H barrels will already have a rough chamber shape only requiring the finish reamer for a full chamber. Basically you’re looking at new barrels for the rough reamer. Perhaps Jeffe could clarify whether McGowen uses both rough and finish reamers for his AccRel cartridges.
Full-length resize reamer - ???...Again you’re call.

I added some additional edits to the reamer print post which hopefully clarifies the print.

I designed the 404-375 H&H Magnum using QD and then annotated the PT&G reamer print with the relating chamber specifications.

The reamer print specifies a chamber length of 2.8701” in length…”bolt face/rim” junction to “neck chamfer”; this accommodates a cartridge length of 2.85” plus an allowance of 0.0201” for brass “growth”.

Regarding the “parallel sided” neck area; it is my understanding that the chamber specification even in the neck area should note a taper for reliable extraction. I did check my PT&G Book of Chamber Prints and both the .458 Lott and the .458 WinMag note a straight taper from the “belt/case body junction” to “Neck Chamfer” for the chamber print…no parallel sides in the neck area.

However in QD I did keep a parallel sided neck area in the cartridge specification; the “bolt face/rim junction to “shoulder/neck junction” is 2.4976” in length, then a parallel sided neck length of 0.3524”, for a total of 2.850” in cartridge length. I believe this is a reloading die issue.

Let me know where I'm wrong.

Well it is good to have a place like this to get help because from people who have experience with new carts the reamer is where a lot of mistakes are made. That is why AR is so great.
I think one thou is normal for neck taper on most carts but I have seen specs for parallel sides too like the Capstick ect.
Yes a full length resizer.
I wager most conversions will be from 375 HH's but it will be good to have a full reamer. 375 people could get away with a 404 neck/throater reamer done by a local smith and order reloading dies from our choice of die maker.
The first time around having a full reamer would be best and would not do any harm if done right.
I will ask some people here for input on what the reamer dimensions should be before talking to Dave.

Talked to Rich about this. He is going to post later on what we need to talk to Dave with.

boomie invited me
don't bother with a rougher .. buy a reloading die reamer instead

don't bother TiN or other coating .. you have a straight taper case here... its easy enough to resharpen .. i think 35 bucks .. when tin coated, if you resharpen once, its just a pretty gold color .. will save you heat treating time

if it where ME, and i had a 375 reamer, i would just order a necker and then take annealed 375 dies to bore out a set

kiff does good work... so does manson .. i just happen to prefer, for no other reason than having a great series of transactions, manson .. manson's drawings make better sense to me.

So your wisdom is to use a 404 neck/throater for 375 conversions and a 375 reamer with a removable 404 pilot reamer for a 404 barrel swap?

Do you now anyone who can bore out 375 dies?

The good thing is that we have the two options to chose from.

I agree Manson reamer prints make more sense as well as a nice guy.

anneal 375 hh dies and ream them out with die reamer .... add a .424 expander,.....

if i were doing it, i would probably either cheap out on a necker, which probably WOULD leave a ring, or go all in and get chamber and die reamers

Boom,

I totally understand what you’re saying. Here’s some data for everyone to chew on:

A few Minimum Chamber Specifications:
375 H&H Magnum:
Diameter at Belt-Case Junction: .5142”
Diameter at Shoulder: .4484
Length to Shoulder-Neck Junction: 2.4976
Length to Neck Chamber: 2.8701
Diameter at Shoulder-Neck Junction: .4051”
Diameter at Neck Chamber: .4039”

404-375 H&H Magnum Current:
Diameter at Belt-Case Junction: .5142”
Diameter at Shoulder: - - - -
Length to Shoulder-Neck Junction: - - - - (@2.4976”)
Length to Neck Chamber: 2.8701
Diameter at Shoulder-Neck Junction: - - - - (.4627”)
Diameter at Neck Chamber: .4540”


404-375 H&H Magnum Revised:
Diameter at Belt-Case Junction: .5142”
Diameter at Shoulder: .- - - -
Length to Shoulder-Neck Junction: 2.4976
Length to Neck Chamber: 2.8701
Diameter at Shoulder-Neck Junction: .4552”
Diameter at Neck Chamber: .4540”

458 Winchester Magnum:
Diameter at Belt-Case Junction: .5150”
Diameter at Shoulder: - - - -
Length to Shoulder-Neck Junction: - - - -
Length to Neck Chamber: 2.5201”
Diameter at Shoulder-Neck Junction: - - - -
Diameter at Neck Chamber: .4831”

458 Lott:
Diameter at Belt-Case Junction: .5150”
Diameter at Shoulder: - - - -
Length to Shoulder-Neck Junction: - - - -
Length to Neck Chamber: 2.8197”
Diameter at Shoulder-Neck Junction: - - - -
Diameter at Neck Chamber: .4831”

470 Capstick:
Diameter at Belt-Case Junction: .5150”
Diameter at Shoulder: - - - -
Length to Shoulder-Neck Junction: 2.4017”
Length to Neck Chamber: 2.8697”
Diameter at Shoulder-Neck Junction: .5059”
Diameter at Neck Chamber: .5049”

Let me know if you want to leave the chamber print as is or if you want a defined chamber neck area; the PT&G reamer print can easily be modified.

This is my OPINION, based on what has worked for me wildcatting for thirty years. It's not the only, it might not be the best way, but it IS what has worked well for me all these years and about twenty wildcats.

1. Determine your wildcat case dimensions. IN this case, Boomie has been able to make a dummy that is usable by the reamer maker. Here I
FL size a 375H&H case and expand the neck to seat the .423" bullet.
2. Order a two reamer set, with the "rough" reamer .002" smaller forward of the belt than the dummy. Order the "finish" reamer .002" larger
forward of the belt.

The rough reamer is used to make the FL sizer die(s), and then to chamber the barrels. In this case the sizer expander ball is .001 under bullet size. IE .422". This is to provide adequate neck tension on loaded rounds.
The finish reamer is used to make the expander ( to flare case mouth .424" for cast bullets) and seating die(s), and then finish chamber the barrels.

This way you have dies to fit the chamber, and the .004" total clearance is plenty for hunting rifles. You can cast gas checked bullets for quarter a round 2100+fps practice loads. Five bucks for twenty rounds of 90% powder loads will encourage you to shoot every week. You can step up to fast reloads on sticks and offhand, and be READY for that trip to Africa in six months!

This works, has since 1978 for me.

Rich

PS: count me in on the cost for the reamers, etc. I have an early FN Mauser in 375H&H Improved I had thought to sell. I think it is going to be a 404/375 instead.

Just read the part about altering 375dies, why not just have CH4D make us ten sets. When you anneal and then reharden dies they CAN distort.
On eight or more sets we can get a great price from Dave.

Rich

Ok so Oscar wants a chamber and die reamers so what dimensions do you suggest? Capo has posted some good info. Capo, thanks for the great info.

My original thinking was to go the easy and cheap route but I understand the desire to do the two reamer set.

How much expansion do we need at the neck area?

Thanks for the input. Much appreciated.

quote:

Originally posted by jeffeosso:
anneal 375 hh dies and ream them out with die reamer .... add a .424 expander,.....

if i were doing it, i would probably either cheap out on a necker, which probably WOULD leave a ring, or go all in and get chamber and die reamers

Awesome news Rich!!!

Could make a nice article

quote:

PS: count me in on the cost for the reamers, etc. I have an early FN Mauser in 375H&H Improved I had thought to sell. I think it is going to be a 404/375 instead.

Thanks for the great input Rich.

A 404-375 will be much better than a 375 improved anyway

quote:

Originally posted by Idaho Sharpshooter:
This is my OPINION, based on what has worked for me wildcatting for thirty years. It's not the only, it might not be the best way, but it IS what has worked well for me all these years and about twenty wildcats.

1. Determine your wildcat case dimensions. IN this case, Boomie has been able to make a dummy that is usable by the reamer maker. Here I
FL size a 375H&H case and expand the neck to seat the .423" bullet.
2. Order a two reamer set, with the "rough" reamer .002" smaller forward of the belt than the dummy. Order the "finish" reamer .002" larger
forward of the belt.

The rough reamer is used to make the FL sizer die(s), and then to chamber the barrels. In this case the sizer expander ball is .001 under bullet size. IE .422". This is to provide adequate neck tension on loaded rounds.
The finish reamer is used to make the expander ( to flare case mouth .424" for cast bullets) and seating die(s), and then finish chamber the barrels.

This way you have dies to fit the chamber, and the .004" total clearance is plenty for hunting rifles. You can cast gas checked bullets for quarter a round 2100+fps practice loads. Five bucks for twenty rounds of 90% powder loads will encourage you to shoot every week. You can step up to fast reloads on sticks and offhand, and be READY for that trip to Africa in six months!

This works, has since 1978 for me.

Rich

PS: count me in on the cost for the reamers, etc. I have an early FN Mauser in 375H&H Improved I had thought to sell. I think it is going to be a 404/375 instead.

So Rich, Looking at the reamer print above what would you change?

So you suggest Oscar sending a few loaded rounds to Dave but letting him know we want the reamer to be for a 2.850" brass length round.

Boom,

From a clean design standpoint, the neck dimensions for the Revised 404-375 H&H Magnum can be set at tight or as loose as you want. That said the recommended dimensions for base…shoulder…and neck…minimum allowance is .004” for standard hunting chamber and .005” for dangerous game chamber.

Here’s a chamber neck dimension reference comparisons:

404 Jeffery, aka: 404 Rimless Nitro Express:
Diameter at Shoulder-Neck Junction: .4559”
Diameter at Neck Chamber: .4532”
Difference: .0017”

404-375 H&H Magnum Revised-Current:
Diameter at Shoulder-Neck Junction: .4552”
Diameter at Neck Chamber: .4540”
Difference: .0012”

And from my earlier post, the data differences between the two neck diameters were:
375 H&H Magnum: .0012”
470 Capstick: .0010”

Issue of reamers and dies:

From my telephonic discussion with Dave Kiff in November, 2009 I know PT&G was working the various reloading die manufacturers for some type of royalty arrangement so that PT&G could provide both the reamers and the relating reloading dies to their customers as a combined order.

If PT&G cannot yet provide finished reloading dies with the relating chamber reamers, an option would be to approach Manson to produce both reamers and reloading dies.

Again more great info. Thanks!
I have heard one of the secrets to the 375 success was the taper in combo with the belt meant it could fire without fail even in a dirty or sloppy chamber. Most woul agree this is a DG hunting round and so 5 thou sounds good to me. What say y'all?
Does anyone know if the modern chambered 375 has a 4 or a 5 thou chamber slop?

IMHO, which is JUST and ONLY that; the .004" will work well. That extra .001" means you work the brass 20% more. I am guessing most of you are not in position to anneal brass after every firing. I have one of the Ken Light automated models and access to a lead pot for the retro look.

Rich
DRSS

quote:

Does anyone know if the modern chambered 375 has a 4 or a 5 thou chamber slop?

Only way to know would be with a chamber casting of your rifle for use to compare against the ammunition you intend to use.

Basically you’re looking at the plus/minus manufacturing tolerance individually for the barrel chamber, the brass wall thickness, and the bullet diameter and then how they collectively combine. A max-plus chamber combined with max-minus brass and bullet and you’re “loose” compared to the design specification. Inversely a max-minus chamber combined with max-plus brass and bullet and you’re “tight” compared to the design specification.

Great talking to you Jim

Likewise Boom …sorry for the delay in posting this.

Here’s the new draft from our telephonic conversation:

The chamber’ neck dimensions were set at 0.004” larger than the neck diameter of the cartridge – projected at 0.448” diameter at the case mouth.

Oscar can you measure the neck dimensions of the dummy round that you created and post here to verify against the new draft chamber print?

If I may, gentlemen. Dave at CH4D just called me about dies. He says it will be simple to change a few lines of code and make the die sets. If we order six sets, there will be no extra charge AND he will give us the 10% writers discount he extends me. How does one hundred dollars a set on six or more sound? If the group likes this, capo could send this line drawing and he will get them started. He would like ONE check and ONE address to ship to, but I think we can send a check and the addresses and he will ship individually for the extra $5 apiece for Priority Boxes.

Time to fill out your dance cards, the band is tuning up...

Rich

Hello Gentlemen,

Sorry about any delay,I have been working late.

Capoward, My dummy round measures .4430 at the neck.This is with expanded brass therefore a little thinner all around.Your numbers look spot on.And the print is wonderful.

Idaho S., that die deal sounds great.

Looks like everything is coming together just right. Oscar.

Hmmmmm...
I thought 12 thou was thin.
.423 + .012 x 2 = .447

Your brass is 10 thou neck?

I would think that 12 thou plus 4 for slop was a good idea.

I guess we need people to measure neck thickness on a variety of brass but I was thinking 12 to 13 would be the norm.

Boom,

Welcome to the world of CIP/SAAMI...establish a standard while attempting to accomodate manufacturing variances worldwide.

Help me out here y'all...
Should 12 thou be the spec standard?

Seems Dago Red is building one now. see the work in progress here.

http://forums.accuratereloadin...241051031#6241051031

Oscar,
So I think it is safe to say we have the reamer dimensions figured out assuming that we agree 12 thou neck thickness per side is agreed. Send Rich a PM He has a variety of HH brass to send you to neck up to 404 to see actual neck OD.

CH4D does not need a reamer to make dies. we just need to send the dimensions.

quote:

Originally posted by oscar:
Hello Gentlemen,

Sorry about any delay,I have been working late.

Capoward, My dummy round measures .4430 at the neck.This is with expanded brass therefore a little thinner all around.Your numbers look spot on.And the print is wonderful.

Idaho S., that die deal sounds great.

Looks like everything is coming together just right. Oscar.

So who else wants to be in on the group dies order?
so far we have
1 Oscar
2 Rich
3
4
5
6


We need at least 6. I can be on the list too but I cant build a rifle yet.

Along with the group buy for dies...
What is the interest for headstamped brass?
Qual-Cart can do smaller runs as low as 250 pieces. I would want 50 myself.

Gentleman,

You don't have to have a rifle ready to build, I am going to wait until my dealer gets in a few .375 Win's. and hand pick one for the 404-375 build.

This may take 6-months to a year. Even though, I still want to accumulate everything I need so when the time comes I'm ready to go.

There is nothing that says you cannot buy your dies & brass now and have your rifle built down the road,especially since we may get a deal on a group buy.

Oscar

I'm sold. Can't do the rifle now, but would like the dies and 50 brass as well. Sounds like I can finally afford to get into a real big bore! Many thanks to all of you guys doing all the hard work. Again, please count me in.
thanks
Rick

Boom,

By the way I'm good for 100 rds. for formal wear.

I'll just make my own from Win. .375's for everything else. Oscar

A hundred and twenty-five, if the tariff is not TOO steep!

Rich

I called Pete to check on price, turn around and minimum order. I hope he can use the headstamp tools on hand to do the job but might have to wait a few months to get the proper stamp if he needs to order a new one.

I was thinking the headstamp would read Quality Cartridge for the manufacturer as he always does and then was thinking a simple 404-375 What say y'all? Do we need HH at the end or will 404-375 be enough?

With a few others joining in it would bring the price down a bit. The more ordered the cheaper it gets. And with a real headstamp brass we will go from Wildcat to proprietary round.

Welcome to the revolution Rick

quote:

Originally posted by foxhound:
I'm sold. Can't do the rifle now, but would like the dies and 50 brass as well. Sounds like I can finally afford to get into a real big bore! Many thanks to all of you guys doing all the hard work. Again, please count me in.
thanks
Rick

Here is a pic again to help visualize
458 Lott, 404-375, 375 HH



So with your quota we could order brass pending confirmation of a few things.

We still need 3 more for dies

BTW this is the largest thread ever on the Wildcat forum. It is great to see people come together here to make this happen and this month is my 5 year anniversary here. This cart getting made will be a good way to round up 10 years here.

If .404-.375 H&H is not to difficult I would go that route since I'm presuming most rifles that will be converted will already have .375 H&H on the barrel.

It may take longer, but the cases & barrels will be legit.

Boom,

Congratulations on your ten year mark. Oscar