PDA

View Full Version : rechambering 30-30 to 30-30AI


micksis86
January 14, 2010, 07:23 AM
Hi,
I'm seriously considering rechambering my marlin 336 30-30 to 30-30 Ackley Improved. I'm wondering what would be involved in doing this?
Obvioulsy the barrel is already .308 so would it just be a case of a gunsmith recutting the chamber?
Thanks

mapsjanhere
January 14, 2010, 08:19 AM
Finding a gun smith that has the reamer for it will be the tricky part. Otherwise it's just reaming and checking the head space. So why you would do that is beyond me, you go from a 150 yard deer gun to a 160 yard deer gun and the most widespread ammo to a home-brew only.

benny7mmWSM
January 14, 2010, 08:22 AM
i never heard of a .30-.30 ackley imp. thats a new one.

mapsjanhere
January 14, 2010, 08:56 AM
The wikipedia article on Ackley (http://en.wikipedia.org/wiki/P.O._Ackley) has a picture.

JackL
January 14, 2010, 09:42 AM
Don't know where you are, but I'm almost 100% certain that Jim Fleming, at Fenris Wolf Arms (http://www.fenriswolfarms.com) in Red Oak, Oklahoma, can do this with little to no hassle. You might want to talk it over with him and see if it's a good move for you.

Disclosure: I'm not a representative of FWA, just a very satisfied customer.

brickeyee
January 14, 2010, 10:24 AM
To get a true Ackley chamber you have to set the barrel back.

Sam06
January 14, 2010, 10:32 AM
I am not a gunsmith but I have a few AI guns and a few 30-30's. I reload for all of them. I think you would be giving up some reliability in a lever action by switching to the AI Version of the 30 WCF. The sloping body of the 30 WCF is made that way to function in a Lever action. The Lever action does not cam like a Bolt gun and you could have sticky extraction or even extraction problems. It could effect the feeding also.

The 30WCF can be boosted with careful handloading and bullet selection. Using a 130gr bullet will push your PBR farther.

A 30 WCF is a great cartridge and with good loads will take deer to 200yds. The gain in fps of the 30 WCF AI would not offset the reliability issues that could come up for me.

Now if you are talking about a Rem 788 or a Savage 340 bolt action 30-30. Or a single shot T/C, that would be a different matter all together.

I am sure there are a lot of people that will disagree with me but thats my 2 cents worth............The 336 is a good gun the way it came from the factory. If you want a flatter shooting lever action look into a savage 99 in 300 savage or 308 Win.

micksis86
January 14, 2010, 11:47 PM
I see all your points I am a big fan of 30-30 my main reason was to give something different a go. I did imagine that the shape of the improved version would effect feeding. Maybe i'll leave it as is it is one hell of an accurate 30 WCF. Might leave it thanks for all your input.
I wouldn't think that a 200-300fps improvement in velocity would make the rifle a 150yard into a 160 yard.

mapsjanhere
January 15, 2010, 08:53 AM
My point was less in regards to the starting fps but to the fact that you're still shooting a flat tip bullet from a lever action gun. F-150 even with a 400 HP motor is still a truck and will never out run a corvette.

Malamute
January 15, 2010, 12:05 PM
You can still shoot factory ammo in the AI chamber.


There's several guys on leverguns forum that have AI's. The discussion has come up a number of times, and you can get some real world info. I think the 200-300fps increase is a bit optomistic.

If you go to shootersforum, there's a guy named williamiorg thats done a lot of work and posted about it, with standard rounds, and the AI's, as well as the 307 and others. He's a wealth of info.

You can gain much of the difference between the standard 30-30 and the AI version with certain powders, and gain trajectory improvements with proper bullet selection (there's a difference in ballistics coefficients with various bullets available). When so loaded, the expensive leverevolution loads dont offer much real world improvement.

micksis86
January 16, 2010, 07:48 AM
Thanks for all you opinions guys, you may be right that 200-300fps is optimistic but i'm just going off data that i've read.
Anyway i've opted to stick with the 30-30 I've taken the stance if it ain't broke don't fix it so i'm going to stick with the trusty old 30-30.

Bud Helms
January 16, 2010, 01:59 PM
To get a true Ackley chamber you have to set the barrel back.

An Ackley Improved chamber is a change in the chamber dimensions from the neck-to-shoulder junction back toward the head or rim. The neck-to-shoulder junction does not move. It does not require a barrel set-back if done correctly.

I have a .30-30 AI in a little NEF rifle. Of the AI chamberings whose parent cartridges have survived til today, the .30-30 is one of the most efficient and returned one of the best increases in velocity. Supposedly it is better than 10%. The brass lasts longer and I bought my .30-30 AI die set from RCBS.

AI is not the best or most cost effective treatment for every chambering. But in certain cartridges it can yield a big step in performance with little more than the cost of the reamer and a knowledgeable person to use it.

I would not AI all the chamberings in my safe, but I've never regretted this particular experiment with the .30-30.

Each chambering is a tale all it's own. Some AIs show increases in only one or two commercially available bullet weights. There is a different gain for each bullet weight in nearly every chambering that gets the AI treatment. Of course handloaders know that each load is a collection of variables, each of which may affect the result. The AI is just one more thing in the mix. I never heard of it hurting a rifle's performance, but it may not be worth the trouble in every instance.

Scorch
January 16, 2010, 02:07 PM
An Ackley Improved chamber is a change in the chamber dimensions from the neck-to-shoulder junction back toward the head or rim. The neck-to-shoulder junction does not move. It does not require a barrel set-back if done correctly.Absolutely true. The reason most AI rechamberings get set back is because of most factory chambers being at maximum length and the person doing the rechambering wanting to completely clean up the chamber. But it is not necessary. I have seen several rechambers done by PO Ackley himself that did not completely clean up the chambers in the neck/shoulder junction area.

mananer
January 18, 2010, 11:17 AM
Just a thought but would the leverevolution loads from Hornady be an option instead the Ackley in 30-30?

brickeyee
January 18, 2010, 05:17 PM
An Ackley Improved chamber is a change in the chamber dimensions from the neck-to-shoulder junction back toward the head or rim. The neck-to-shoulder junction does not move. It does not require a barrel set-back if done correctly.

Try it.

You cannot remove the metal you need without at least touching the neck shoulder joint.

The 'go gauge' is the Ackley 'no-go.'

You may end up with something with a 40 degree shoulder, but it is NOT a correct AI chamber.

You need a crush headspace to ensure safety when firing factor non-AI ammunition, and you cannot get that without setting back before cutting.

sonic1
January 21, 2010, 11:20 PM
on some cal. a full 1 turn set back is not needed ..the last .222 mag. i did only needed a 1/2 turn..witch was ok because it had no sights..i think some set back will be needed on all old chambers...but then again...........i"ve read Ackley made all AI so that factory ammo can still be safely fired in them...

F. Guffey
January 22, 2010, 12:29 AM
The 30/30 Winchester and the 30/30 Ackley Improved are two different chambers and are not similar as with other improved chambers, the shoulder on the Ackley version is moved forward .150 thousands, the Ackley improved version has a case neck length of .350, .076 shorter than the 30/30. There is no need moving the barrel back to remove all of the chamber.

F. Guffey

F. Guffey
January 22, 2010, 12:05 PM
30/30 Winchester tapper, 30/40 Krag tapper, 303 taper, 300 H&H and the reason why, that was the old days when there was a transition from black powder to smokeless, there were no options as to case capacity and burn rate, a larger case capacity offered no advantage and the tapper was easier to form, when we noticed the 7mm57 had less tapper and by that time DuPont snuck/sneaked across the Atlantic and went to work for a foreign smokeless powder company, then he snuck/sneaked back with the receipt and everyone was happy.

http://www.cowart.info/Florida%20History/Dupont/Dupont%20Biography.htm

F. Guffey

brickeyee
January 22, 2010, 12:34 PM
on some cal. a full 1 turn set back is not needed ..the last .222 mag. i did only needed a 1/2 turn..witch was ok because it had no sights.

Many AIs can be done with less than a full turn of setback.

It is the presence of sights that often drives a full turn.

The problem is that for the original round to headspace correctly the shoulder must be re-cut.

If the chamber is so short it will not close on a 'go' gauge you might get there, but that means the chamber was incorrect to start with.

Lawyer Daggit
January 22, 2010, 12:58 PM
I had my TC carbine .30-30 barrel ackley improved some years ago and all i can say is do it- the result is revolutionary, esp when pointed bullets are used.

It also created a situation where my pointed 30-30 ammo could not be chambered in my lever action .30-30.

Now that you can get pointed bullets for lever guns improvement may not be so great.

jaguarxk120
January 22, 2010, 09:10 PM
I always thought the 30-30 headspaced on the rim not the shoulder.

F. Guffey
January 23, 2010, 10:45 AM
The 30/30 (rimmed and belted cases) head space on the rim and or belt, in the perfect world the case would head space on the rim and the shoulder, when it becomes a choice the head spacing on the shoulder increases case life by cutting down on all that case travel and the hand loaders insistence on full length sizing the case. For hand loaders there is nothing between full length sizing and neck sizing.

"To get a true Ackley chamber you have to set the barrel back" 'True'.

There are two Ackley chambers, straight out of the box Ackley Improved chamber and The 30/06 chamber that is reamed to Ackley Improved, there are two of those, the set back barrel version and the chamber that is still retains a small portion of the 'Old' chamber. Then there is the one where the operator of the reamer gets creative and makes up things as they go by advancing the reamer beyond specifications, cases will be fire formed, that makes up for some of the mistakes and short cuts.

"An Ackley Improved chamber is a change in the chamber dimensions from the neck-to-shoulder junction back toward the head or rim. The neck-to-shoulder junction does not move. It does not require a barrel set-back if done correctly".
To get a true Ackley chamber you have to set the barrel back.



"Absolutely true. The reason most AI rechamberings get set back is because of most factory chambers being at maximum length and the person doing the rechambering wanting to completely clean up the chamber. But it is not necessary. I have seen several rechambers done by PO Ackley himself that did not completely clean up the chambers in the neck/shoulder junction area"

The two statements above is the reason the question is never answered and when the question comes up again it is the same as starting over, I had this discus ion with a smith in Arizona that went by the name Seaweed. He sent drawings and then went back and reexamined the information he sent, then said "I never noticed that before, the neck on the 30/06 Ackley is longer than the neck on the 30/06 Springfield. We are not talking about the 30/06 or Ackley, we were talking about my methods/techniques, something he described as "Some scary stuff", I also talked to Hodgkin, they said 'IT' will work and I will tell you why.

Back to the genius's of Ackley, and the misconception the datum is in the center of the shoulder (that is imposable), the juncture of the shoulder at the end of the case body moves forward, the juncture of the shoulder at the neck moves back and there is a point on the shoulder that does not move (similar to + caster, move the top forward the bottom moves to the rear when supported in the center. The plan: When the short neck 30/06 is chambered in the Ackley version of the 30/06 the short neck must be sized in the long neck of the Improved chamber (head space, sorta) when fired the case blows out and forms the rest, the shoulder and body, again when chambered the neck is formed when the bolt closes, the rest is formed when the case is fired.

Point being to clean up the chamber the barrel requires setting back, if the barrel is not set back forget head spacing on the neck.

Datum half way between the shoulder to case body juncture and the shoulder to neck juncture and head space gage, done correctly the go-gage is the go-gage, the no-go gage does not become anything but the no-go gage, unless the person operating the reamer designates the no go-gage as the go-gage. The Datum does not chage except on the Internet, meaning the datum on the 30/06 is the same for the Ackley Improved version, 'the genius's of Ackley, same case, head space on the neck juncture, use the same gages.

The 30/06 case neck is .031 thousands shorter than the Ackley Improved neck, going to the no go-gage length gage changes the neck length from .031 to .026 thousands. When going to the 30 Gibbs the shoulder is moved forward .212 rhousands, no barrel set back required.

http://www.z-hat.com/Cylinder.htm

F. Guffey

F. Guffey
January 23, 2010, 10:53 AM
discussion, thousands,

sorry about that,

F. Guffey

Bud Helms
January 24, 2010, 02:22 AM
Guffey, brickeye, thanks for the info. I was unaware of that, but it makes sense.

I learned something once again. I've been meaning to go measure the neck length on my .30-30 AI vs a normal case. I will do that and bring the numbers back here. Of course it will depend on how my smith did the chamber. He may not have understood this stuff either.

brickeyee
January 25, 2010, 03:40 PM
If you are going to use the method Ackley write up, the go-gauge becomes the AI no-go gauge.
Since every gun should close on the go gauge, you are going to have to set the barrel back if you want to use the go gauge as a no-go gauge and ensure you can fire the original parent cartridge in the new chamber.

You can also cut the chamber as deep as you want, but without a reliable way to headspace the original cartridge you are left with other methods like expanding the neck, then creating a new false neck for initial fire forming.

Part of the attraction of the AI cartridges is the ability to fire the original case safely and form the AI case.

While Ackley may have created other cartridge designs by not setting the barrel back, they are not in keeping with the methods outlined in the Handbook for Shooters.

Bud Helms
January 25, 2010, 04:33 PM
Yes, I can see that on a rimless case, i.e., .30-'06.