Your own cases tapped fo the Hornady O.A.L Gauge

[ovenpaa]

What size drill and tap do you use what size is the tap thread.

I am at work and they are at home, I will have a look tonight.

[Dangermouse]

I started this venture the last time Ovenpaa and I shot with ex skydiver last month. Over a cup of tea I was complaining that whenever I use the standard Stoney-point OAL tool and case that I find that I can actually load rounds (comparatively) much longer than the tool suggests.
Between us we agreed that the reason is probably because the case that comes with the tool is a standard .308 Winchester case and that you would need a custom case fired from your own rifle to get the degree of accuracy that I was after.
It was felt that such cases were available but at a price, also rumour had it that you could buy the tooling your self but also at a price.

The conversation stuck in my head and I wanted to find out how much the tooling would be. I continued the conversation with 20series a week later and asked him how someone would work out the thread on the Stoney Point tool to make your own cases. 20series suggested that a interned search would bring up the answer and it did very quickly, it appears that this is a common topic in the US and you can even buy the tools as a set on US ebay - although that dealer will not ship to the UK!

A quick search of ebay did find a dealer that would ship to the UK and surprisingly fast the items arrived, with on this occasion, no further costs.
These are the items that I purchased for Ovenpaa to use. I don't know if he used the drill bit or had something else:

.2969 19/64 HSCO TiN STUB DRILL
http://cgi.ebay.co.uk/2969-19-64-HSCO-T ... 45fb937b83

5/16-36 GH2 HSS 4 FLUTE PLUG TAP
http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0576692997

The only further tooling that should be required is to open up the inside of the neck enough for a bullet to slide easily in and out. Clearly this is calibre specific, unlike the other two tools.

Before any one orders anything please wait for me to make sure that the thread that Ovenpaa has put on the cases does fit on the OAL gauge, it is just possible that something somewhere has been changed.
Christel will be posting the cases to me this week and I will let you know how it all compares with the standard case when I get them back,

DM

Edit:
That seller charged me $13.95 postage on top of the prices that you see listed.

[ovenpaa]

Before any one orders anything please wait for me to make sure that the thread that Ovenpaa has put on the cases does fit on the OAL gauge, it is just possible that something somewhere has been changed.
Christel will be posting the cases to me this week and I will let you know how it all compares with the standard case when I get them back,

The cases went out last night, I built my own OAL tool and used a fine metric thread so I could not check the ones I built for you yesterday however it did look OK size and threads per inch.

I just did a quick search and the thread size was confirmed on a US forum, however I did see a few UK shops list it as out of stock right now. From memory they are around GBP30 each which seems excessive to me and I am tempted to make a couple more myself in case anyone ever needs one.

[Alpha1]

I will have a look to morrow see if my suppliers stock them.

[ovenpaa]

The tap I have via DM is a 5/16-36 with a 19/64 drill however I tend to drill slightly under size (6.5mm) then bore to tap size and put a slight chamfer at the start of the thread to ensure there will not be any burrs.

[Alpha1]

All I can say folks is if you want any modded cases you should take advantage of the mans offer and cross his palm with the price of a couple beers.

I can see why they use this thread on there OAL gauge cases it is a very rarely used instrument gauge thread.

To buy this tap in the UK would not be cheap.

Luckilly I have a old guy that we dragged out of retirement who comes in a couple days a week who is a guru with this type of thing he loves making Enfield threads.
(In fact now I think about it most of the people I work with including me have been dragged in out of retirement were is all the new blood)OOps I am rambling again.
Any way he is going to make me a tap set in fact he is going to drill and tap a case for just about every caliber I have on Thursday just have to work out what job number I am going to charge his time to. :lol: :lol: :lol:

[Dangermouse]

After 2 days of rain the post man decided to pay me a visit today and dropped off a pile of post which included the cases.

Initially when I looked at the thread I though OMG that is way too big a hole, but no need to worry it does fit on the Hornady/Stoney Point OAL gauge - perfectly!

To see if it was actually worth the bother I took a few measurements,
With me reducing the size of a case with a bullet in .005 at a time, I make the OAL (to ogive) to be 2.150" That method entails making a round, minus primer/powder and making it too long so that the bolt does not close. Then reduce it gradually till the bolt does close, but probably with resistance. Then a final amount so the bolt closes without resistance.

Using the Hornady case it measured the OAL to be 2.142 - so a little disparity.
With my cases in the Hornady rig, as made up by Ovenpaa, I get an average of 2.155

So there I have it, it was worth doing and should I want to build a round so that it is touching, I can now do it with confidence. I can also measure any wear on the throat over time.
My current bullet is the 185gn Berger which was reasonably tight in the neck, I think I would prefer it slightly looser so that I know that I am not ramming it in, but I am sure that it will wear lose in time and that other makes/weights will be different.

Go Team Dave

DM

[ovenpaa]

DM, if you are to use this to monitor throat erosion make sure you always use the same case. Also it sounds like the neck is still a tad too tight, I tested them with a 155 Scenar of unknown state as opposed to a new shiny one but the neck should be at .309" right now.

[spud]

DM, if you are to use this to monitor throat erosion make sure you always use the same case. Also it sounds like the neck is still a tad too tight, I tested them with a 155 Scenar of unknown state as opposed to a new shiny one but the neck should be at .309" right now.

and the same bullet as ogives do vary as we all know

[DaveT]

Ovenpaa... I would be very grateful if you can do some for me ..... i will contact you when I get back from holiday if thats ok?

Cheers

DaveT