I have a friend that loaded up some 55 gr Nosler BTs in .243 Win using 50 gr. of H380 powder. He stated that this was 2gr below max in his Nosler book so we decided to try them. Upon trying them at the range, we were getting velocity in the 4020 fps range. This was with a factory Remington 700 .243 with a 24" barrel.

With that said, I didn't think I'd ever see 4K+ fps velocity from a .243. Anyone else seeing this kind of velocity with a similar charge? Brass had no swipe marks but primers appeared fairly flat.

I was over 4000fps with H414 from a 22" barrel, brass life was ok, flat primers, easy bolt lift. It was awesome on coyotes, ground hogs and crows.

Same here, 4100 fps with a 26" barreled M-70 heavy varmint using RL-15 to push the 55 gr NBT's and yes, it's pure venemous hell on coyotes.

Gunner

Those 55 noslers are great little bullets...darn accurate and hold together.

Here's an even crazier idea...a 300 wsm pushing 125s to 4000 fps...
http://bulletin.accurateshooter.com/2007/09/franklins-4000fps-30-cal-varminter-a-hit-with-hunters/

I've seen over 4000fps out of several rifles with several different powders in the 243 win with 55gr BTs ; really not hard to do.
That velocity you are seeing does seem fast for that charge weight of H380 though. That would have matched up with somewhere around 3800fps with H380 according to Nosler's fifth edition manual.
They start at 49grs for 3783fps and go up to a maximum of 53grs for 4069fps in that book ; this out of a 24" Lilja match grade pressure test barrel which generally run faster velocities that a factory barrel will.
Nosler doesn't list H380 in their #7 Manual.
I would personally be a little leery of that load when the temps* warm up ; H380 is pretty temp* sensitive, and if your getting that type of speed now my guess is you're running more pressure than you think in that barrel.
Good Luck,
Ted

I have with a 26" tube and the 55 grain

works faster from a 240 bee.

The old Hogdon site use to have two sets of data, one for 55s up to
3900, and another 4000 and up.

Now the site has changed and I haven't
spent a lot of time on it

Steves pages has a lot of good stuff too..

I would inclose a link, but I have a new computer and cant find anything.

I bought some 55s just to see 4000+ on the chrony, and did.

You should see what that combo will do to a crow.

55's in a 243??? While other guys shoot a 75 in a .223??? Very interesting stuff.. I bet they would destroy a crow or coyote... Lightest I ever shot were 60 gr. Serria and 65 grain Vmax. Deadly..

LOL, I bought some 45 BK's just to see 4500 on the chrony, and I did !!!!!!!

Tried some 6mm 55 BT's once, decided it didn't offer me nothing more than higher cost. I see 55's @ 3900 + all the time.

Over the years, I've seen greater variation in published loads for H380 than for any other powder.

Yep, H-380 is kind of unpredictable when it gets warm and working max loads. In that scenario I move to AA 2700. 55's go 3900 + out of Swift. 26" tube without being at max. Doesn't behave badly like 380 can in hot weather. If I go with a mag primer it gives me a little more velocity.

I have at least 50 different powders in my gun safe now and have tried several others that I wont use again, but hands down the most temp. sensitive powder I have ever used is H380.

It is worse in some chamberings than others, for example it works well in a 22-250 but is dangerous in a 220 Swift.

I use it in a slow twist 6BR but would never use it in a 243Win....JME

IME it can vary greatly from lot to lot of powder and is very temp* sensitive.
I've also shot some great groups & dumped a lot of coyotes with it,
But grew weary of the variable changes ; don't load it much these days ; to many other good powders around....

Me too!

I have used H-380 in 223, 243, 22-250, and the Swift. Even tried it in a 25.06 but found I should have used a magnum primer for better ignition. It's not dangerous in any of those calibers especially the Swift if you know when to back it off. Shot more 380 and 2700 in the 250 and the Swift than anything else. Right now the other good powders don't seem to be readily available , 380 & 2700 are. So when others can't find their favorite powder and have to let them sit, I will have loads for them all that work using those two and keep right on shooting.

Swifty52,
I've shot H380 in all of those rounds - for years.
I never said it was dangerous - just inconsistent - which it has been IME.
There are other powders that can be used in a pinch with just as good of results, but if you still like those two knock yourself out - but don't think you're the only one who knows how to keep shooting when supplies are tight.

This thread was about the 243 - not the 22-250 or the Swift - nobody asked about those - that's not really going to help the OP much.

Sorry you got clicked on but no reason to get the panties in a bunch, look and read the post above yours for the word dangerous, and comment not suitable for 243 Win. But if you all want to burn up a 243 barrel for no good reason, then go ahead BTDT. The 55 grain BT offers nothing that a 22 cal. 55 doesn't except more powder useage & expense for bullets. BTDT too.

I've ran the 55's over 4000 for years from a 6mm. I use either Benchmark or H4895 and both are consistent.

Bb

I don't have any panties to get in a bunch, you must have them confused with what you like to wear.

I wasn't upset ; just stated some simple facts.

It would probably be best if you didn't post your cross dressing tendencies in a public forum ; might make people see you in a bad light....

Just so you know ; you're completely off the thread topic again..

Regarding the use of a 55 gr in a .224 cal vs .243. The Nosler 55 gr varmint bullet has a higher BC in .243 than .224!

.276 vs .267 sure it isn't much but interesting.

I also got 4050 fps with a 55 gr in a .243 24" barrel and varget.

The 6mm-284 also 24" barrel was 4200 without pushing it.

Both 6mm chamberings shot that 55 nos bt quite accurately too.

How hard would these loads be on a barrel?

same bullet throttled down to 2700 fps MV, is actually a very good bullet for deer the size of those AZ Coos deer... or any deer that may be antelope sized...a hint if you are looking for something for the kids to shoot deer with out of a 243...

and yeah, I've field tested it....and have loaded it up for several local jr deer hunters on their first deer hunts with successful results...

I have been happy with the 70 gr Blitzking for varmints in my .243. How does the 55 gr compare at extended range and in the wind? I may be persuaded to switch...though the Blitzkings have been shooting bragging-sized groups.

You might find this interesting.

It appears that there is little difference in ballistics between a .224 and .243 55gr bullet at 4000 fps.
However, getting a .224 bullet to 4000 fps may be a bit trickier unless you are shooting a 224 Weatherby Mag. I see you are coming close with a 220 Swift and 26inch barrel but I suspect (yeah I know, no proof) that this isn't much easier on barrels than it is in a 243.
No right or wrong answer-just different ways of achieving the same result.

Actually the 243 should/could/would/will throat out quicker. It takes roughly 10 grains more powder to get a 243 to that point. On mine it took 52 grains H-380. 243 win is just like the swift in barrel burning reputation, around here the 243's get put away after deer season.

Dang it, I might have to try some 55's just for fun. I have some laying around and some Varget, 4064, and R15.

I got well over 4000fps with 55/58's in a .243 with 22' barrel and H-4895 these loads shot Ok to so-so throat wear was serious in a short period of time, personaly I will stick to 70's for light bullet in a .243 , less throat wear per volume and much better accuracy . IME

H4895 is a good powder for popping 70-75 grain pills out of a 243. That is my standard load for yotes when I take it instead of one of my 22's. Very accurate, shot very well in 300 yard score matches a number of years back. Problem is that throat erosion always happens when using large charges of slow powders like 380 & 2700 which is what will get you 4000 + fps in a 243. 4064 will get you there too. Awful lot of heat and pressure 53,500 I do believe is what gets you there, which is exactly why I quit using 55's and 4000 fps loads in mine. It's to accurate of a rifle to destroy it just for chits and giggles. My 22.250 was purchased just to shoot fast bullets, but when the speed devil is being chased it just didn't quite catch it. The swift was purchased just for chasing the speed devil, burnt up the first tube in 4 years, 52 grainers clocking just under 4100 took it out quick, throat erosion showed up at the 200 round mark, barrel was toast by 400 round mark of using that load. Figure it will go back to cooper next year again for another tube as 52 & 55's going 3900 isn't any easier on the throat.
Chasing the speed devil is a losing proposition.