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Is this safe...Hurry before I blow myself up!!!
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Member Posts: 168,427 ✭
I just had a new rifle built in .300 Win A.I. and my new chamber is .077 shorter than the factory .300 Win was. The old chamber was 2.955 from the head of the case to the ogive where it meets the rifling. The new chamber measures 2.878 to the ogive. I have a bunch of old reloads that I want to use to break my barrel in with and the bullets were seated to an overall length of 2.950 to the ogive. I just finished seating these a little deeper to the overall lenth (to the ogive) of 2.868 which should be .010 off the rifling. I do not remember what load was used with these reloads. In your opinion (no, I won't hold you to it[;)]), am I safe to fire these in my new rifle. I cannot see why not, but something is bugging me about it...Thanks for the feedback!
Eric
allamericanarmsco@frontiernet.net
All American Arms Company
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Eric
allamericanarmsco@frontiernet.net
All American Arms Company
www.galleryofguns.com
VIP Code: AAAC
Veteran Owned and Operated
Comments
gun control is not about guns, it is about CONTROL!
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When you say headspace I refer to the shoulder length. If the cases chamber without forcing them too hard your headspace is good. If you are going to the AI chamber with standard cases you should have a little bit of force to get them to chamber but not a lot. The standard case will fireform out to the AI case.
Now for the C.O.L. question. If your bullets are .010 off the lands you will be safe, provided the load is normally safe. If your bullets are in the lands you will not be safe unless you have these tolerances checked and cleared by a benchrest knowing gunsmith. The only bullets I use that go to(at) the lands are Bergers. Some benchresters seat some of their bullets into the lands. Again, this is a practice that is really only safe in a very close tolerance rifle that has been worked on to make it safe.
We have the second amendment so that all the rest are secure....UNK>
None of the above really matters in the short run or the long run.
There is no reason to shoot these ever. Unload them no matter what. Your safety is the most important thing here, not a few cartridges.
I'm not trying to be rude to anyone but Ackley or not, safe starting load or not, these could prove to be very unsafe. You don't remember the load and we certainly don't know so why even begin to take a chance. It's silly. To be absolutely safe you need to unload these cartridges and start over and work your way up to a safe load at the length that you have chosen to work with in your new rifle's chamber.
Headspace for a belted magnum is from the base of the cartridge to the front of the belt until and if the cartridge is fireformed in the chamber and the shoulder is not set back when reloaded.
Best.
Eric
allamericanarmsco@frontiernet.net
All American Arms Company
www.galleryofguns.com
VIP Code: AAAC
Veteran Owned and Operated
I gotta say that I have to agree with nononsense, JuctC and Brier-49. I apologize that I wasn't adamant enough about your safety to say you should have pulled the bullets. You now know two things.
1. Keep records on your loads and know the relative pressures you are working with. Anything loose that you don't know where it came from doesn't have a record.
2. When you don't know what is in something you reloaded a while ago pull the bullets and start from scratch. Safety is, in the long run, more economical than a couple of bullets.
We have the second amendment so that all the rest are secure....UNK>
Your chamber must press an unloaded case against the boltface with the decreased datum line of the ackley shoulder to be correctly done. Also,..I HIGHLY recommend jamming the pill into the lands by a good .010" to get a compressed chamber fit. The ackley needs to get it's brass flow from the neck and NOT from the casehead area. Once they are formed, seating can be changed,..but I ALWAYS jamm my fireform loads.
why chase the game when the bullet can get em from here?....
Got Balistics?
Do you load full power rounds for the fireforming or slightly/a lot reduced? All the firforming I ever did with the .257 Rbts AI was shoot factory loads. Those were pretty mild to start with.
Note: that is what I meant also in my earlier post about having to use a little bit of force to close the bolt. Ackley's, at least the one I worked with, had a (like you said) .002" short chamber so you would get a good seat on the shoulder/neck area.
I would presume though that ECC's gunsmith should know this.
We have the second amendment so that all the rest are secure....UNK>
why chase the game when the bullet can get em from here?....
Got Balistics?
You certainly have to like saving the barrels, raising kids and having room for a custom barrel is pretty hard to do. Next time I go with an Ackley(I almost did this time with the 6mm Rem AI, but decided for feeding purposes the standard Mauser case would be a little simpler) I will give that a shot.
I don't know if it is related but when working up the Swiss 7.5x55 in my K-31's I noted they have a blown out shoulder from the standard 7.5. I noted also that they shoot standard cases almost if not as accurate as the reloads I shoot using the Redding die that gives the closer tolerance on the shoulder. The whole situation with them reminds very much of Ackley's cartridge design principle. The parent cartridge is every bit as accurate as the modified.
We have the second amendment so that all the rest are secure....UNK>
Now from what I understand the 257rbts is one of, if not THE case that gains the most from the AI conversion. So, when you are blowing out that much case, you are certainly using a bit of the pressure to blow out the case body which "should" decrease the pressure curve as the internal capacity is increasing 3 dimensionaly. Not only is the bullet moving away from the casehead which increases the compression chamber size, but at the same time it is growing much more 360* around as the body taper is removed than it would in the parent chamber, and this further increases the size of the compression chamber and speeds up the decrease in pressure.
why chase the game when the bullet can get em from here?....
Got Balistics?
Years ago when I worked with my friend on loads for his .257 Ackley We noted that we got good factory accuracy out of the box nothing better than what I got out of my dads .257, 1"-1 1/2" groups. It was a different story when we took some of our handloads and ran them through his Ackley. That's when we started getting 1/2" -1/4" groups. Of course he got that with his handloads after that.
Most people say that the .257 Rbts AI was Ackley's best work. Ackley said his best work was the 250/3000 AI. He got better than standard .257 velocities with it. His .257AI only equaled 25-06 velocities. Either way, I wouldn't mind having both...or all three. I would really like to see something for the .25 cals in a 1-9" twist or 1-8" twist and start seeing some bullets in the 125-135 range. The market will need to drive that though.
My mention of the 7.5 Swiss being similar in character and possibly having influence on Ackleys work coincides possibly with the fact that he was earning his degree in engineering while the K-31 was being developed. Who knows?, quite possibly the similarity isn't just a coincidence. It does lack his signature 40* shoulder though.
We have the second amendment so that all the rest are secure....UNK>