22-250 8 twist groups

[josebd]

Who knows?

 

[mike mccormick]

A Merlin race block is based on a cast iron BBC, that doesn't imply that you'll ever compete successfully using a 1972 454 block from grampa's old station wagon....

To actually answer your question, perty much every successful wildcat is based on something already available. The 22-250 falls short in a variety of areas, the biggest being that the angles used preclude good resizing. The low shoulder will always slip and makes precise chamber fit problematic......The excess body taper also makes extraction difficult and the large primer makes it impossible to get the pressure up for a clean burn......ALL problems identified and SOLVED in the CM round.

 

[mike mccormick]

So I guess the 6mm International, in its many subtle iterations, was just a big olle turd, huh?

 

[Evan]

A Merlin race block is based on a cast iron BBC, that doesn't imply that you'll ever compete successfully using a 1972 454 block from grampa's old station wagon....

To actually answer your question, perty much every successful wildcat is based on something already available. The 22-250 falls short in a variety of areas, the biggest being that the angles used preclude good resizing. The low shoulder will always slip and makes precise chamber fit problematic......The excess body taper also makes extraction difficult and the large primer makes it impossible to get the pressure up for a clean burn......ALL problems identified and SOLVED in the CM round.

Sorry, Al. I think that's B.S. and I half think you're just trolling here. You've made sensible comments in other thread sin the past; this is the first that has struck me as ridiculous. First off, josebd is the guy who is just trying to figure out why his trap speed isn't what it should be when he dynoed 500whp the day before. He's not trying to make his 500whp Camaro trap 200mph. Now to the "problems":

• I don't even know what you mean by the angles precluding good sizing. Can you explain what you mean? There is no unusual trouble bumping shoulders 0.002 or sizing the necks with even off-the-shelf dies. Works perfectly, just like with any other bottleneck brass cartridge of the last century that isn't overly work hardened.
  
• The 22-250 has a 28 degree shoulder, which is much steeper than the 23 of the 222, or the 20 of the 308. Both of which are known for exceptional accuracy and no "slipping" issues at all. It's also only 2 degrees less than the modern "standard" of 30. It's clearly not going to cause head spacing issues or we'd have heard about it before now.
  
• Excess body taper causing extraction issues? What kind of extraction issues are you talking about? Maybe if your chamber is polished mirror smooth or your case is oiled and you're getting bolt thrust. Otherwise,it works perfectly fine, just like with any other bottleneck brass cartridge of the last century. There is a large amount of surface area for the brass to grab and the body taper is just about 1 degree which would actually make it easier to extract the brass after firing vs a straight wall (less friction).
  
• The large primer causing an unclean burn just sounds silly to me in this context. I'm running single digit SD and low teen ES with my 22-250 with large primers. This isn't a PPC and he's not trying to achieve those levels. The only ignition issues I've heard of have been with spherical powders that are known to be difficult, but a small primer doesn't fix that, it's just the physical/chemical reality of that powder type. I just don't see this as a problem, especially not at ~0.5MOA.

Ultimately I'm befuddled and angry that folks are telling josebd that he can't expect more than what he's getting from a 22-250. Better 0.5MOA is not a high hurdle. It's not like he's trying to go from 0.2MOA into the teens. Maybe this really is the limit of his equipment, but it's NOT an inherent limit of the 22-250.

 

[alinwa]

Sorry, Al. I think that's B.S. and I half think you're just trolling here. You've made sensible comments in other thread sin the past; this is the first that has struck me as ridiculous. First off, josebd is the guy who is just trying to figure out why his trap speed isn't what it should be when he dynoed 500whp the day before. He's not trying to make his 500whp Camaro trap 200mph. Now to the "problems":

• I don't even know what you mean by the angles precluding good sizing. Can you explain what you mean? There is no unusual trouble bumping shoulders 0.002 or sizing the necks with even off-the-shelf dies. Works perfectly, just like with any other bottleneck brass cartridge of the last century that isn't overly work hardened.
  
• The 22-250 has a 28 degree shoulder, which is much steeper than the 23 of the 222, or the 20 of the 308. Both of which are known for exceptional accuracy and no "slipping" issues at all. It's also only 2 degrees less than the modern "standard" of 30. It's clearly not going to cause head spacing issues or we'd have heard about it before now.
  
• Excess body taper causing extraction issues? What kind of extraction issues are you talking about? Maybe if your chamber is polished mirror smooth or your case is oiled and you're getting bolt thrust. Otherwise,it works perfectly fine, just like with any other bottleneck brass cartridge of the last century. There is a large amount of surface area for the brass to grab and the body taper is just about 1 degree which would actually make it easier to extract the brass after firing vs a straight wall (less friction).
  
• The large primer causing an unclean burn just sounds silly to me in this context. I'm running single digit SD and low teen ES with my 22-250 with large primers. This isn't a PPC and he's not trying to achieve those levels. The only ignition issues I've heard of have been with spherical powders that are known to be difficult, but a small primer doesn't fix that, it's just the physical/chemical reality of that powder type. I just don't see this as a problem, especially not at ~0.5MOA.

Ultimately I'm befuddled and angry that folks are telling josebd that he can't expect more than what he's getting from a 22-250. Better 0.5MOA is not a high hurdle. It's not like he's trying to go from 0.2MOA into the teens. Maybe this really is the limit of his equipment, but it's NOT an inherent limit of the 22-250.

Nice post Evan. You sound reasonable so I'll try to explain my position.

(BTW AFAIK I'm the only one "telling him it's all he can expect")

I say that because I've spent a lot of time with the round. Back in the 70's it was the hottest thing on the planet. I graduated and went to gunsmithing school and was introduced to PO Ackley and others through books. In the 80's I worked hard and got some dream guns..... of course several were 22-250's. I also met some Bench Rest guys. I got to see what guns COULD do. I met guns that DID make one hole and cases that DID last for 50-100 reloads and guys that DID step up to the plate and show it. And for the next ten years I spent tens of thousands of dollars trying to prove that "regular chamberings" (like 22-250) could shoot just like benchrest chamberings..... if only they were built the same.

And I found out WHY Parker Ackley "improved" cartridges, and why the 22-250AI was the one he called "best to improve." Also worthy of note is that while the shoulder angle is 28 degrees off centerline it's actual working angle at the shoulder is less than that due to the body taper.

I spent some years and lots of money on the 22-250. And I couldn't get it to do what I wanted it to do. And with the tapered case I always fought sticky extraction. (I didn't KNOW it was the case taper, but I fought with case growth and stickiness) I've since learned that tapered cases tend to stick just like a Morse taper sticks. It can't "get out of the way" when it collapses after firing...

I then switched gears to an "Improved" round. I tried working with the .243AI........5 platforms, 4 reamers and 7 barrels....... and it solved some of the problems. Sticky extraction was gone.... and I re-read PO Ackley...."AHA! THAT's what he was talking about!" But still just couldn't get what I wanted and case life wasn't great. The 40* shoulder didn't lend itself to good sizing either.... case life sucked.....


I finally bit the bullet and started checking out 22BR, 6PPC, 6BR and was blown away..... HEY! Them BR guys was on to something! (Took me 15yrs to believe them that "Hey kid, we've BTDT that's WHY we do it this way...")


I built my first successful full-on ground-up wildcat as a shortened 308. The only thing it was missing was the small primer......

I begged and pleaded with Kaltron Pettibone to send me basic 308 cases with no primer pocket nor flashhole....

Then around 2003 I felt ready to tackle a 6mm tight-twist world-beater. A 22-250 sized case but in 6MM. Minimum body taper of .010tpi, 30* shoulder, tight radius transitions n/s and s/b..... all the good stuff.

Some guys were blowing out Dan Dowling and Al Ashton's "22 DAsher" to 6mm corrupting it to 6 Dasher in the process

The 6MM-250 was gaining a following

GDavid Tubb was designing an industry to implement and support a new "6XC" and

I decided to go with something completely different, HOPING for a case that wasn't even on the horizon.... I took my 308-.200 and necked it down to 6mm, ran a 6BR reamer in deep and ended up with a fat-butted 6MM, a long-version 6BR about like the "Dasher" only with a neck.

Money and time/time and money and all'ofa'sudden "GLORY HALLELUJAH!!!!" KP announced "A new 6.5 rd tentatively called the 6.5 Lapua" which ended up as "6.5X47 Lapua" which I adopted as mine (my dies even fit it!) Just freaky-cool.

I wrote about it back in 2009 here http://benchrest.com/showthread.php?58805-Al-s-6x47L

WARNING TO ALL WHINERS..... DON'T CLICK, IT'S LONG AND INCREDIBLY BORING AND FULL OF 10-YRS-AGO ALINWA.... you will HATE it....

And since then things like the 6.5 Creedmoor have debuted.

ALL USING THOSE SAME RULES, all exhibiting similar characteristics of the basic 6BR (the magical case that spawned this forum, among other things!)..... guaranteed to work because DESIGNED to work.

I've since applied these same rules to a variety of cases, the latest being the .338 Lapua Magnum. I had done a lot of research looking for a big 338.... The 338L was close but had some of the same problems I'd experienced 20yrs ago with the 22-250. Looking at the case it's somewhat like the 22-250 in shape. So I bought a couple boxes, measured them up and ordered a reamer listed at PTG as the 338 McCallum. It's a smashing success.


Sooooo...... my assessment of "best it can be" is based on the following assumptions.
-gun is chambered in factory 22-250 SAAMI spec (neck is too wide among other things. in-bore yaw can't be avoided)
-op is probably using factory dies so fit is not adequate.

What I see is a beautiful platform with an inadequate chamber.

I'm happy to be shown wrong.

And I'm certainly not dis'ing the op as you and others seem to think..... this IS A DISCUSSION FORUM..... I am sharing my opinion.

My opinions have been changed many times through the years by time spent on another forum, now I'm trying to help another.

Sorry you've taken it as pissing on your cheerios, I gave an opinion, MINE.

 

[Intheshop]

To the OP..... what's the round count and how is the barrel working,as in fouling/cleaning?

 

[josebd]

Round count 50,new shilen,cleans up very easy,no copper fouling

 

[Rstrick0352]

Round count 50,new shilen,cleans up very easy,no copper fouling

It'll shoot. Find your node then tune your seating depth, better groups will come.

 

[Intheshop]

Wind skills,bench etiquette,and learning what a barrel "likes" should see those groups close up to..... almost half of your original pic. Folks get wound up about cleaning new barrels..... it ain't about "clean",it's about what the barrel needs,to perform that counts.

 

[josebd]

Going to try it in the morning, I will have wind flag setup.
Going to try 36.3 and 36.5 .010 off lands
36.3 and 36.5 .015 off lands

 

[josebd]

1.36.3 .010 off lands
2.36.5 .010 off lands
3.36.3 .015 off lands
4.36.5 .015 off lands
Looks like #4 maybe go up on powder charge?
H4350,ccibr2,Sierra 77hpbt,200 yards ,with wind flag

 

[Kracken McGraw]

Whatever that second picture group is, I would zero it on the bullseye and call it done.