Rifle build questions inside, experienced opinions needed

Sakoboy

Sakoboy

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I'm thinking of building a long range 22 cal rifle, probably in 22-250.
Sierra and Berger both make 90gr pills with BC's over 500 and Hornady has the 80gr A-Max with a BC around 450.
I understand that I would need a pretty tight twist, somewhere around 7 to stabilize the heavier bullets.

Q - Would I need to keep the barrel closer to the 30" mark to keep the velocities up enough to be supersonic at the 1K mark?
Q - What about case capacity, those 90's are long and I'm not sure what kind of seating depths and powders I'm looking at.
Q - What kind of barrel wear can I look forward to? 4000-5000 rounds would be nice, I’m sure it won’t get that high, but it can’t be any worse than my 243.
Q - Is this a practical build (Caliber) for it's intended purpose.

It will be for plinking, hogs, paper, etc, nothing serious.

Jump in and tell me what you think.

I'll probably build it like my 243 & 308

243308.jpg
 
You would be fine with almost any length of barrel for velocity at 1000M

You will be generating tremendous pressure with a big bullet in that case but powder options are huge 4895, 4350, varget, etc. I would expect your load to be somewhere in the 30 grain range

Barrel wear with a good barrel will be kinda harsh. 2000 rounds or so

Practical? From a barrel life perspective, there are probably better combinations. but other options include the 22BR, a plain 223 (Lots of barrel life there) and lighter bullets.
I would also consider a 6mmBR shooting 90 grainers... 3000 fps+ and plenty of energy and superlative accuracy to 1000M
 
A 22/250 would be great for pushing these heavies and not stressing anything.

26" is plenty long. 28 or 30" is fine too.

Just remember that you can't run these heavies too fast or they will blow up. Think 3200fps as an operational max. 7 twist will do the job.

I have shot 80gr bullets to a mile with a 223 so anything bigger is just gravy. wind drift is alot less with the faster velocity.

You will not get very high barrel life if run at max performance. 2000rds sounds about the right ballpark for 1/2 min or better accuracy. But you can load up or down as you see fit.

Will be alot of fun.

Jerry
 
2000 rounds, that's it, darn... oh well, you cant win them all. ;)

Thanks for chiming in guys, I was hoping you two were going to show up and give me advice. :D

If its not to much trouble, could one of you explain to me why a 308 can get near 5000 rounds but a 243 is closer to 2000. (I'm using this example since they use the same casing)
At equal velocities (lets say between 2850 & 2950) out of identical rifles, a 308 will throw a heavier bullet, use more powder, and still get twice the life of a barrel that a 243 gets. :bangHead:

One more question guys, with everything being equal, what kind of barrel life will a 260 get, lets say throwing 140's?

I really appreciate your time and I value your opinions.
 
Ultimately

you get to choose what caliber YOU want to use for your long range gun.

I personally would NEVER build a long range gun based off a 22 cal chamber.

6mm would be the minimium.

This is MY opinion though.
 
Barrel wear is directly related to how much powder you burn relative to bore size.

So burning 42gr of powder in a 6mm is more erosive then in a 338. That is why the 308 can get such long barrel wear.

Pressure also plays a role as that will increase flame temp.

Why a 22/250 burning 36gr of powder is as erosive as a 260 burning 46gr.

So to answer your second question, the 260 will get 1500 to 1800rds of accurate fire when pushing 140's at desired pressures.

But the chamberings that wear out faster will also have much reduced wind drift at LR.

So a 260/140gr going 2750fps is going to have 1/2 the wind drift of a 308/168 going the same speed. That is what you get for 1/2 the barrel life.

Hope this helps...

Jerry
 
i don't quite understand the wind drift equation in the last post. could somebody explain this to me?
i thought a heavier bullet going the same speed would have less wind drift>
 
BC is a number talked about alot in LR shooting.

It is a relative measure of how well a bullet goes through the air. Its drag coeffecient. Mass and calibre are 'calculated' out to crunch this number.

So bullets of the same BC have the same relative shape/drag regardless of how big or heavy that bullet actually is. ie a 80gr 22cal Berger VLD has the same BC as a 175 308MK. They will travel through the air in the same trajectory if launched at the same velocity.

Short stubby and heavy will not compete with long skinny but light at long distances.

The short/low BC bullets slows down too much so takes longer to get to the target which allows wind more time to push it off course.

Jerry
 
Yes Jerry, actually it helps allot. It never fails, I read on CGN everyday and everyday I learn something new and walk away knowing a little more than I did yesterday.
Keep up the good work guys. :cheers: Oops, and gals. ;)
 
Case capacity in grains of H20 divided by the area of the case opening (pi*r squared) in inches results in a relative index number to give a very good predictor of accurate barrel life. An "Overbore Index"

22-250 = 43 grains of water multiplied by the area of a 224 cartridge (.112X.112X3.1415) equals 1091.

A number below 800 is fairly good (308 and 223 are in about 750, 760). Above 1000 is definitely into overbore territory. A 300 Winchester Short Magnum has an index of 1060, and the 6.5X284 (known as a barrel eater, good for about 1000 rounds) has an index of about 1200.

This is a cartidge with a high overbore index and as such its performance comes at a cost.
 
We need a list (sticky)

Ok, now it's all coming together, what we need now is a chart that we can look through and find out which cartridges are barrel burners and which will give a longer barrel life. There has to be a chart out there on the Internet somewhere, I'm sure in todays society of statistics that somewhere, somebody went to the trouble of creating such a list.
 
I have just built a 22/250 for varmints. Savage precision action, 28 inch bbl. I limit it to 600 yds using a 60-70 grain bullets. Beyond that I use a custom 6/284. Because I do not shoot them in matches, the barrels will last a least 10 years. I do not care about barrel burn. If I am still alive I will get a new barrel.
 
Worse. It would be right up there with the 25-06 with an OBI of about 1250, good for less than a thousand accurate rounds more than likely. It will shoot and still shoot minute of moose heart for some time Like most overbore cartridges, but in terms of competitive accuracy, not long.
 
Yikes... makes me afraid to ask about my 204! :D

Minute of heart will mostly be good enough for me as far as hunting goes. Right now it's in its early hundredths. Gotta love the 7WSM, despite the overbore index! :)
 
Theoretically, a 22 calibre wildcat shooting a 6mm or even a 6.5 would dramatically increase barrel life. (well maybe not dramatically but you get the point).

I'm under the impression that accuracy and velocity are the main reasons for wildcatting at the expense of barrel life, is this accurate?
 
Not always at the expense of barrel life... 30BR, 6X47(old), 30X47 Lapua. Some wildcats are extremely accurate and better on barrels.

Wildcatting is all about the pursuit of the bigger-better mousetrap. For every far-out widcat design out there, there are a hundred gray-haired guys that achieved the results they were after with a plain old 30-06 and a 6.5X55, and probably did it better
 
The 6.5 and 6X284, 22/250, 25-06, 7-08, 260R, 17 FB, 6PPC, 6BR, 6.8SPC, all the standard magnum Weatheby's, 300 and 338 RUM, 338 Federal, 35 Whelen, etc.

These were all wildcats by changing the neck of some parent brass. Some improved the performance. Others were just done to use a different calibre. They just happen to have become so popular that a major manf has 'adopted' it as a factory cartridge.

Quite a number of modern cartridges come from wildcatters and their 'better mousetraps'.

17Rem has a near identical case capacity to the 223 so you can use that to start.

Jerry
 
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