How fast can a 60gr boolit a 22 Cal 16" twist barrel be driven?

[303Guy]

The idea is to use a 22lr barrel for high velocity cast. The case would be either a 303 Brit necked down, maybe shortened or a 222. The question is how fast? Also, which is better, a smaller volume case or a larger volume lower pressure case? I am talking 1 in 16 twist so muzzle blast may be a problem if too much. I know that a 22 hornet with 1 in 16 twist does stabilize a 60gr spire point. I'd be looking at a shorter flat nose boolit, maybe a little heavier.

[enfield]

I couldn't get my 22lr barrel to stabilize a 55 gr lyman boolit. I didn't try to drive them very fast because the first few loads were keyholes at 25 yards so I figured there wasn't much hope. I'm sure it was also 1-16" and chambered to 22 hornet.

[Forrest r]

Don't know if this helps but:

Aguila makes a 60gr bullet for 1 of their lines of 22lr ammo.

http://www.midwayusa.com/product/461399/aguila-sss-sniper-subsonic-ammunition-22-long-rifle-60-grain-lead-round-nose-box-of-500-10-boxes-of-50

Enough people have had trouble with this ammo/bullet tumbling in their standard 1 in 16" twist bbl's that companies have made/chambered 1 in 9" twist bbl's to specifically shoot the heavier bullet.

http://www.midwayusa.com/product/739376/volquartsen-match-barrel-ruger-10-22-22-long-rifle-920-diameter-1-in-9-twist-for-aguila-60-gr-sss-ammunition-18-1-2-stainless-steel

[303Guy]

I've shot 55gr RCBS FN's in my hornet and apart from less than stellar accuracy, they seemed to work fine. A boolit like that in the transonic range would be hopeless, I'd imagine. Not sure about subsonic - that might need more twist rate.

I can do a test using my hornet (just thought of that) with 60 grainers although if they work in the hornet won't necessarily mean they'll work in a bigger case due to muzzle blast destabilization. Perhaps I should make a mold and start casting! I could probably get them up to 2650 fps.

Interesting that a purpose barrel is being made for those 60gr 22 lr subsonic's. But why so fast a twist? Then again, why not.

[mikeym1a]

I've shot 55gr RCBS FN's in my hornet and apart from less than stellar accuracy, they seemed to work fine. A boolit like that in the transonic range would be hopeless, I'd imagine. Not sure about subsonic - that might need more twist rate.

I can do a test using my hornet (just thought of that) with 60 grainers although if they work in the hornet won't necessarily mean they'll work in a bigger case due to muzzle blast destabilization. Perhaps I should make a mold and start casting! I could probably get them up to 2650 fps.

Interesting that a purpose barrel is being made for those 60gr 22 lr subsonic's. But why so fast a twist? Then again, why not.

I got a replacement barrel for my AR-7 from ar7.com. I asked and it is a 1/14 twist. Haven't had a chance to try it out since i got it. :sad:

[303Guy]

How long is it? I'm wondering about muzzle blast with the idea that muzzle blast is a big destabilizer.

[Forrest r]

They went to the faster twist (1 in 9) on the 22lr bbl's because it was hit & miss with the standard bbl's (1 in 16 twist) to be able to stablize the heavier 60gr bullet.

With most standard bbl's the heavier 60gr bullet would tumble badly, enough that they make a special 1 in 9 bbl for them.

The 60gr 22lr bullet is only rated @ 950fps at the muzzle.

[Pakprotector]

Y'all might want to play around with this twist v. stabilization factor calculator embedded in the page.
http://www.border-barrels.com/barrel_twist.htm
cheers,
Douglas

[Pakprotector]

There is a discontinuity at speed of sound...Bad Things no doubt happen there. Kinda like the 'Here Be Monsters' notations on olde maps...lol
cheers,
Douglas

[Larry Gibson]

303Guy

3000+ fps is doable with accuracy if a large enough case is used. Psi should be under 42000 so athe 22-250 is about the smallest case to use. I don't think the 22LR barrels have deep enouph rifling. A quality CF barrel of 26 - 28" length would be best to use in your quest.

Larry Gibson

[303Guy]

Thanks Larry. Well then, I might have to forget high velocity and go for a slower flat nose or semi-round hollow nose at max weight. To be legal for hunting it needs to equal or exceed 222 Remington ballistics (not that anyone will actually measure it - as long as the case looks bigger it'll be fine, and I'll make sure it does have enough muzzle energy, even though it won't be used for deer).

That's an interesting stability calculator. It shows what I've been trying to re-find for a while, that being that the faster the boolit the higher the required twist rate up to a point, which flies in the face of conventional thinking that driving a boolit faster in a given twist makes the boolit more stable. It actually makes the boolit less stable - to a point. However, bullet form plays a major role and might even reverse that. What this calculator doesn't seem to take into account is muzzle blast (it has no case volume or powder charge and barrel length inputs). But then again it gives a stability factor of 1.5

[303Guy]

I couldn't get my 22lr barrel to stabilize a 55 gr lyman boolit. I didn't try to drive them very fast because the first few loads were keyholes at 25 yards so I figured there wasn't much hope. I'm sure it was also 1-16" and chambered to 22 hornet.
enfield, playing around with that bullet stability calculator, it becomes very clear why the 55gr Lyman boolit wouldn't stabilize - it needs about a 12 inch twist to stabilize at subsonic velocty. At super sonic it would need about an 18 inch twist, increasing as the velocity increases but still staying below 16 inch (or something like that).

[mikeym1a]

I believe that the .22 Hornet was developed from the .22WCF, using modified .22rimfire rifles. If that's the case, don't know why it wouldn't work. The question is, what .22 rimfire barrel has a breech big enough for the proposed cartridge? Or do you intend to sleeve it?

[303Guy]

I intend to screw the barrel into a chamber piece. It'll be a bit heavier than a normal chamber to accommodate the threads. I'll cut the throat into the barrel and the chamber end will be the junction although I could put the junction at the shoulder base. I'm thinking chamber end so as to make cutting the throat easier and would also make it easier to redo if I get it wrong.

[mikeym1a]

Some time back I got a replacement barrel for my AR-7. It's .827 dia, and 16"long, with a 1/14 twist. It is listed as a target barrel. I got it through AR7.com. I haven't tried any of the 60gr rimfires, yet. Need to soon, though. That barrel, and the big scope I put on it make it no longer a 'pack' rifle.

[williamwaco]

Larry + 1.

I thing chambering a rim fire barrel for a center fire cartridge is a really bad idea for several reasons.

[303Guy]

I thing chambering a rim fire barrel for a center fire cartridge is a really bad idea for several reasons.Would you care to elaborate?

It might be Ok for 22 hornet class performance but I am coming around to it being a bad idea. It might be better for me to use a larger case for lower peak pressure and hopefully a slow pressure rise. I am beginning to think I should find a take-off 224 barrel, or better yet, a 25 barrel (243 might be easier to find. There is a fair priced 7mm barrel out there).

[Nickle]

For all the trouble to do this, I would think it would be smarter to start with a 224 center fire barrel, preferably with an appropriate twist.

Now, I have used a 1-14" twist 22-250 (22" or 24" barrel, Rem 788) and 63 grain Sierra bullets for hunting before. Accuracy @ 100 yards was pretty good.

We do know that 223 Rem, 1-14" twist and 62 grain boat tail bullets aren't a real good combination. 1-9" twist is a different matter.

In the end, I would recommend a 223, 22-250 or 219 Don Wasp with a 9" twist for this. It would also allow you to go heavier than 60 grains, or 55-60 grains and less velocity. The key thing you really want is accuracy.

[303Guy]

It's just that I have the barrels and would like to use them. If I were to look for a barrel I would likely go for a 25 but then I already have one. What I might do is build a 22 cal air rifle pellet firing gun using my long Cooey barrel. That would be tricky but might work with a hornet case using Trail Boss. H4227 works but doesn't fill the case which is needed to stop the pellet from falling back in the case.

[mikeym1a]

How long is it? I'm wondering about muzzle blast with the idea that muzzle blast is a big destabilizer.

It's 16.5" from breech to muzzle, and about 1"diameter.

[RPRNY]

I can't imagine how you imagine a 22 cal bullet of greater than 55 grs stabilizing in anything more than 1:12 unless pushed at velocities unsuitable for less than the hardest and most frangible of lead. My Savage 340 B in 222 Remington (1:14) is a lovely rifle. 52 grs with copper jackets is the longest bullet that I can stabilize with it. How you intend to get anything longer to shoot well without being in the 1:12/14 twist rate I cannot imagine.

[felix]

The 1.5 stability factor is the standard for condom bullets where the condom itself contains the usual 95 percent copper. Making the condom heavier, the stability factor can go down to a general purpose 1.2 for the typical target ranges including ambient and well as distance. That is why the long range accuracy was amazing with the Sharps and other large diameter boolits having sufficient length for the conditions, using relatively slow twists. Twists have to go up dramatically to shoot thick condoms (outside covers for lead, uranium). Talking relative terms here, folks. ... felix

[303Guy]

RPRNY, a spitzer, spire point or round nose increases in stability with increasing velocity and then not by much but perhaps enough to make a difference but a flat nose decreases in stability with increasing velocity. For the weight, a round nose is the most stable boolit form but a spire or spitzer is more stable for the length. I've shot 60gr Hornady spire points with great accuracy out of my 1 in 16 twist hornet. A round nose of that length would be less stable and a flat nose less stable still. But for the same weight, a 60gr or more should stabilize just fine. Subsonic FN requires a somewhat higher twist. Now a boat tail, even a small one destabilizes a projectile a lot so a faster twist is required. That same hornet would not stabilize a BTFMJ at the attainable velocity with that hornet. I'm using BORDER BARRELS BARREL TWIST CALCULATOR, the link having been given by Pakprotector earlier on in post #8.
Here it is again. It's quite revealing. http://www.border-barrels.com/barrel_twist.htm

I did not know what the lower limit SF for lead was. I figured that close to transonic muzzle velocities it might be higher. But since I'd be looking at higher velocities and I would be trying smooth sides, I might try heavier rather than faster although the end purpose may be rabbit hunting in which case range would be the objective so lighter and more streamlined would be the way to go. Accuracy would be paramount of course.

The air rifle pellet rifle would be for rabbit and possum where a 22lr would have too much carry-over range.

[Nickle]

FWIW, I used to have a couple of 219 Donaldson Wasps that had 1-15" twist barrels. One was a Heavy Varmint gun (Weaver T25), the other Light Varmint (Siebert bumped Leupold, 24X). I used 52-53 grain bullets, and they were pretty accurate. Suffice it to say, I shot one group, bobbled the 5th shot a little, still ended up with a .195" group at 100 meters (Heavy Varmint gun). Those were Hart barrels, one on a sleeved Rem 600 action, the other on a Rem 722 action, both in fiberglass stocks, and competitive.

Now, taking all this into account, you might be able to get away with making those 1-16" barrels into 22-250 caliber, and get away with the 60 grain bullet. Stabilization is about bullet length, rather than weight, so using a flat base bullet should work. Cold weather tends to make it worse, but I also used to shoot that HV gun in the winter league at Duham's Bay, NY, and had no issues at -20 degrees or worse. Of course, I used H4895 powder, not the H322 that most of the 6PPC shooters used. They had some awful keyholing issues. So, powder choice is relevant here, as you're already on the margin.

Now, all this said, I still think you'll be better off using a better twist barrel. If you're doing this to experiment and learn, then that's a means to an end all by itself.

And, we do want to hear how it works out, whether good or bad. Your results do matter to some of us, regardless of outcome.

[303Guy]

Thanks for that, Nickle. Maybe I should get on with it. I was just looking at those barrels. I wish I could tell what steels were used. Without knowing I could not risk jacketeds. It also limits flame temperature and chamber pressure. That is another point, perhaps the most important one.