.308x1.6125

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Last Post 30 September 2018
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Ross Smith posted this 20 September 2018

I bought the John Ardito rifle that was advertised here. I'm looking forward to a learning experience, probably a long one given my history.

The rifle came with several formed 308 brass, winchester, that are 1.61+ long so not standard 30 br????????? Searching this site it looks like 21-24 grn Rl-7 was his load????????/ and it was plenty hot. What might be a good starting point, 18 grn rl7, lyman #2 alloy, or harder? The rifle came with 2 Eagan molds,tapered bore rider style. One longer than the other 1.013" and 1.15" I think. The fired cases all chamber easily and if a bullet is finger seated in a case , it goes so far and stops. When that is chambered it has a slight resistance when closing the bolt. When extracting the case, the cast bullet will be seated a shade deeper and there is chamfering around the driving band. Did not see and rifling marks. The brass were all formed from trimmed and sized 308 brass.

Any advice is welcome on loads, brass forming, dies, good dogs , etc . post on the thread or pm me.

Thanks , Ross

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OU812 posted this 23 September 2018

I have the ten piece pilot bushing set for use with my ptg reamer. This helps measure throat/bore diameter when making die. Squeeze down fat bore ride section to fit bore with little resistance.

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OU812 posted this 25 September 2018

My PTG neck reamer was guided using a snug slip fit pilot bushing fitted to bore. Then hand cut using their crude t handle. Reamer also has adjustable stop to cut free bore length. I know this is not the best way to guide reamer, but it did work.

Tom Gray mentioned he machines a hole at primer pocket to guide reamer along with snug slip fit pilot bushing.

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frnkeore posted this 21 September 2018

Is the extra length in the shoulder or the neck?

Frank

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MarkinEllensburg posted this 21 September 2018

There is no standard .30BR. I've read that the outside case dimensions of .30BR = .308x1.5" Inside might be different as the .30BR is generally formed from a Norma 6mm BR. However some are forming the case from a whole host of other parent cartridges. Some believe that large primers are better, some claim primer size does not matter. To make a form die shorten a .308 sizer, remove the decap stem and ream the top of the die to neck diameter, however this might make cases with necks that are too large in OD. It might be best to have one made from the reamer that cut the chamber but with a second hand wildcat you get what you get.

For a load starting point if you can find match data from that rifle it might be worthwhile to copy it as to alloy, primer, powder and charge. If you want a starting load reduce the max you can find by 10%. When I inherited my .30BR it did not come with load data. I first looked at match data in TFS and tried what seemed to be popular. I meanwhile kept researching and finally discovered that my Father was last using Varget in the rifle. I promptly made the switch and accuracy improved. A year ago I made a chamber cast. It took me a year to actually study that cast and understand what it meant: my throat has long since been shot out/eroded. I'm now contemplating reaming it out to .308x1.8" and if I do I know load work up will be all experimentation, no data source known.

Frank asks a great question. Can you post a pic of the case and perhaps a chamber cast?

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frnkeore posted this 21 September 2018

Check your shoulder dimensions, against this 300 savage drawing.

A CBA record holder, in the late 80's, early '90's (Etz Johnson) shot what he called a 1 5/8", long necked, Savage.. Short chambered, with a extended neck. I think his neck was 3/8 long.

The 300 Savage is a excellent cartridge design. I had a 722 Rem and had a Palma neck and throat reamer made to extend the OA case length to 2.03, so that I could shoot full length 308 Win cases.

I've always liked the 30 deg shoulder.

Frank

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Lee Wiggins posted this 22 September 2018

Ross,

Your rifle is probably a 1 in 14 twist Hart stainless barrel chambered 308x1.625 with a tapered throat of 1/2 degree per side ( 1 degree total). . That is what John was doing,he told me .The alloy needs to be harder than Lyman #2. John was using 80/20 Lino/WW.he said the bullets can be too hard. If you have a 1 in 14 twist the load will be 22 to 23 gr of Rx7 , if it is a 1 in 12 twist 20 gr of Rx7 works . I am copying what John did but in a 1 in 12 twist Hart barrel and shooting 1/4 to 3/4 in groups consistently using a Lyman 311284 bullet in 80/20 Lino/WW lubed with Tom Gray #24 Alum. gas check, bumped in a die cut with the same reamer that cut the throat and pushed with 20 gr Rx7.

John taught me a lot hope this helps you.

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Lee Wiggins posted this 22 September 2018

Pic of a recent target. If you can see my note on top right target, the 36 Rx7 is NOT ( Repeat NOT ) grains of powder , It IS the setting on my Culver Conversion Lyman powder measure that throws a 20 gr. charge of Rx7.

Lee Wiggins

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Ken Campbell Iowa posted this 22 September 2018

... great stuff, guys ..... although my guilty pleasures of being a slovenly plinker are rendered almost unbearable when i look at your teensy groups ....

ok, if johna will put together a cheater rig, so then will I ... there:: that is my challenge !! ... after all, i suppose i could still plink with a 5/8 moa rifle ?? ...

**************

would like to see your chamber casting ....

thanks, ken

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Lee Wiggins posted this 22 September 2018

Ken,

I will make a chamber cast this evening and post a pic.

Lee

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Lee Wiggins posted this 23 September 2018

Ken,

Pic of chamber cast, 308X1.625 with bullet seated, Throating reamer with depth gauge (full 308 case). Reamer nose bushing centers front of reamer and 308 case centers back of reamer and is the depth stop.

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Ross Smith posted this 23 September 2018

Lee: Fantastic, you nailed it, 14 twist Hart stainless. I took it shooting today and did bets with 20 gr r-7. But that was only one group. I was "testing" to see where the rifle shot best and the groups closed up at 20 gr and did well thru 24 gr. That's where I ran out of shells. Only have 33. I need to beg, borrow, steal, or buy some forming dies to make some more brass. I'll eventually get to shooting one case all day. I was shooting the 177grn eagan 330 with 2 grease grooves. I also have the 430 which casts 204 grn with 50/50 ww and lino. Still lots to learn about the rifle and the loads. I did out shoot a fellow with his brand new browning 6.5 creedmore.

My chamber cast showed .5 inch of freebore, but the casting wasn't as good as yours.

Miles to go

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OU812 posted this 23 September 2018

Do a chamber cast and measure free bore diameter and taper. Surely someone on this site has a matching throating reamer to make the much needed bump die. I have squeezed down the fat Lyman 314299 bore rider to match barrel,but the heavy bullet caused too much recoil in my 10 pound rifle.7

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Ken Campbell Iowa posted this 26 September 2018

speaking of throat configurations, i offer the following for interest: using three match barrels ( 22 rimfire ) and 4 or 5 different chamber reamers with different throaters ... we found no accuracy difference between zero freebore and a freebore of nearly the length of the groove diameter of the bullet. ....

where cut, freebore was snug fit on bullet taper was 1 and also 1/2 degree.

all three barrels and all combinations shot about 1/2 moa .

we felt there was a slight advantage to a chamber pretty tight at the front of the case.

***************

these were custom chambers, note that factory rifles error toward using any gritty loads you need to shoot at grizzlies and charging rabbits ... but the above points to LBT type chambers might need a more serious try in a competition rig. ( long but tight freebore before rifling. ) weatherby are long but not tight.

ain't this fun ??

ken

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Ross Smith posted this 21 September 2018

Best I can:

6mm br= 1.075 to the shoulder

mine 1.145"

Some of the case are longer 1.618" and that is in the neck. They still chamber. Most of the cases are not trimmed to the same length. Judging from the bullet that I seated with the bolt, there is a long lead. I have not chamber cast yet, maybe tonight.

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rmrix posted this 21 September 2018

I bought the John Ardito rifle that was advertised here. I'm looking forward to a learning experience, probably a long one given my history.

The rifle came with several formed 308 brass, winchester, that are 1.61+ long so not standard 30 br????????? Searching this site it looks like 21-24 grn Rl-7 was his load????????/ and it was plenty hot. The brass were all formed from trimmed and sized 308 brass.

Any advice is welcome on loads, brass forming, dies, good dogs , etc . post on the thread or pm me.

Thanks , Ross"

If you have one of John's rifles and it is chambered like the one he built for me, it is NOT based on the 30 BR.

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pat i. posted this 21 September 2018

I don't know what chamber Ardito used but from what you're saying about the cases its probably 308 x 1 5/8 or that would be my guess. I chambered a gun up in 30x47. I made cases by shortening a 308 die and using 300 Savage brass. That's probably what you're going to end up doing unless you can get a hold of his forming die. Depending on what he did you might end up having to turn the necks. What diameter is the neck on the cases you have with a bullet seated? What diameter is the web on the cases you have? I might be all wet here so doing or having someone do a chamber cast would be a pretty good idea. My best guess though is that he ran a .308 reamer in short.

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rmrix posted this 21 September 2018

" My best guess though is that he ran a .308 reamer in short."

Nope.

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Ross Smith posted this 21 September 2018

I did a chamber cast. And this cat is not a 30br by a long shot. The case taper is close to a 30-06 taper, not a 308 case taper! It has a 30 degree shoulder. So it's a 30 x 1.6125 and is it's own animal. Most of the cases are sized but not trimmed or neck reamed, or fire formed. Lots of fiddling ahead. Going to eventually need case trimmer and form dies.

The cases that have been used have a .312+ inside neck and a .308 shoulder at the base. My guess is that an inside neck reamer was used and stopped short of going all the way down the neck. Bullets are slip fit and stop on the base, they are then final seated in the throat when closing the bolt.

Notes on the baggies that all came in said 308 cases are better than 30-06 cases, I assume form forming. Gonna need a custom sizing die.

Starting load, anybody??????? 18grns. R-7?????????? John's load was 24. I only shoot 20grns r7 in my '06.

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pat i. posted this 21 September 2018

" My best guess though is that he ran a .308 reamer in short."

Nope.

Since you seem to know what it isn't why not just tell what it is.

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porthos posted this 21 September 2018

i have a Ardito rifle that he built for me in 1992. i shot it for appx 150 rounds. i then went back to trapshooting for the next 23 years. so, i didn't shoot it much. mine came with a forming die for the brass, an Egan mold, RCBS rockchucker press and a bullet " forming " die. the bullet die was cut with the same reamer that he throated the chamber with. the press has linkage that ejects the bullet after forming. with the letter he sent me after load testing; he states that the best loads are 24-26 gr. of RL-7 and 27-28 gr. of H332. the bullet weights 195 gr. he sent some groups with the letter. 24 gr RL-7 group is11/16. with H332 3 groups 1/2, 1/2 and 5/8. all 5 shots. maybe some day i may get back to shooting it some more

.308x1.6125

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