270 and 243 MV question

Status
Not open for further replies.
S

Shawnee

member
Joined
Oct 17, 2006
Messages
3,306
Location
Along "That Dark and Bloody River"
Even though I've done a lot of reloading I've never had a chronograph so the only velocity "knowledge" I've had is what has been printed in the manuals.

Some years ago I did some reloading for friends who had .270s and the load they finally settled on turned out to be quite accurate in at least five different rifles (three of which were Remington 700 ADLs). That load was the 130gr. bullet on top of 56 grs. of IMR #4350 - which the book says should be at about 3100fps. I am really curious about that particular load and am wondering if any of you chrono owners have used it (or something close) and have actual chrono results you could share. ???

Ditto my All-Time Favorite .243 load - which is the 87gr. BTHP on top of 42.5grs. of IMR #4350. That one is at a nominal 3200fps according to the book.

Can anyone help me out with actual chrono results for either/both of those loads ???

Many thanks,:)
Shawnee
:cool:
 
243 win. loads Maximum loads Reduce 10% and work up to start

Imr 4350 - 42.0gr, 85 gr Sierra hpbt #1530, Rem 9 1/2 primer 27 1/2" barrel Average 3101fps. Same but with 43.0gr average 3219fps. Winchester brass. Maximum loads, reduce all 10% and work up. Different gun 18 1/2" barrel IMR 4350-42.0gr, 85gr Sierra spt #1520 average 2679fps. Remington brass.
 
I`ve got around 2950 fps with 54.5gr of H4350/130gr Hornady in a 26" BBL. These velocities don`t really mean much to you though. The numbers in the manuals were chrono`ed during the loads development and are as "honest" as any other "chrono`ed" results someone here will offer.

I`ve 2, 260 Rem chambered rifles. One has a 22" tube that shoots ~ 50 fps faster then the others 24" barrel with ammo from the same box. Common thoughts on barrel lgt vs velocity hint that it should be 50 or more fps slower. The short barrel comes very close to book velocity keeping difference in lenght in mind, the other.........go figure.
 
Shawnee, just a curious question here from a friendly reloader. Are you loading for 270 Winchester, 270 Weatherby, or 270 WSM?

I ask because your load of 56.0 grains IMR4350 exceeds maximum for 130g bullet in 270 Win according to the powder manufacturer and according to my Lyman manual. It is not over max if you are loading either of the other two cartridges. I was going to load a few rounds of 270 Win and shoot over the chrono for you, but I stopped because the load exceeds the IMR and Lyman max load data.

On the other hand, different published manuals have different maximum loads, so your manual may indicate that the load is not above maximum. Which manual are you using for reference? If you're loading for friends, you might want to confer with the IMR manufacturer's data just to be extra extra careful with your friends' rifles.
 
Hi "Ants"...

Loaded for the .270 Winchester.

Hornady Rifle-Pistol Vol. II shows a max of 57.6gr. for the 130-grainer with IMR #4350. This manual was published before the Legal Dept. started peddling their paranoia in overdrive.

There were no excess pressure signs and the load was extremely accurate. Thanks for the heads up though.:)

:cool:
 
OK. I'm game. I loaded up one Speer HotCor 130 grain over 56.0 grains of IMR 4350 and shot it over the chrono. Velocity was 3594 feet per second. This is no typing error, that is the actual true number on the Shooting Chrony F1 remote display. I didn't load and shoot another round to verify, I stopped there.

This is a 24" Rem 700. Case is R-P twice fired. The primer is slightly cratered and partially flattened (now has a square shoulder) but there are no other signs of excessive pressure. Unlocking the bolt was a bit stiffer than usual, but not prohibitive. You and I both know that 270 Win is a high pressure round, and we do expect higher pressures than 30-06 and its other sister cartridges. We won't be weenies about it. But maybe it would be wise to borrow a chrono yourself and do a full workup from starting load.
 
:what: 3594 fps ??? That's 200fps faster than this manual shows as the max attainable with the .270 Weatherby !!! :eek::eek:

So much for my naive faith in reloading manuals. Geez ! I've been using this manual for 341 years !

I don't load for the .270 anymore though so am not in any iminent peril. Would be interesting to see what load produced an honest 3200fps (which is what the 56gr. load is supposed to do).

Thanks for the education !!!!!

:eek:

Here's the manual page...

270.gif
 
Never loaded .270 Winchester to date, but . . .

.243 Winchester is a horse of a different color, since it's my precious baby and I understand its specific feedings needed to perform to the MAX. I love the .270 Winchester, but I don't believe it could ever become what the U.S. military is seeking. At 800 yards, a .243 Winchester PERFORMS AMAZINGLY, and at 1000 yards it's as good as any others can get. At these distant targets, a 90 grain Swift Scirocco II is as accurate as accuracy gets. My .243 SUPER SNIPER loads entail the use of Swift bullets and H4350 powder because NOTHING can surpass this combination to date regarding velocity and accuracy combined. The wounding quality of my test loads is 100%. Current military rifles cannot belittle my mil-spec loads to date, and maybe never. Skirting around the issue with strange new cartridges will never surpass the modest-recoiling, though OMNIPOTENT .243 Winchester. cliffy
 
270 Winchester

The Hodgden site list 55gr. of IMR4350 as max at 3028fps @ 49,900 CUP. I'd rather see more than one round on the Chrony to verify those big numbers. I have a few manuals that I'll list the max loads and velocity of IMR4350.
First I have the same Hornady manual as above.
2nd-Speer#7-56.0gr @ 3164fps
3rd-Bob Hagel's Game Loads & Practical Ballistics- 57.0gr@3084fps
4th-Lyman46th-54.5gr@3138fps
5th-Lyman48th- 54.5gr@3032fps
6th-Lee2nd- 55gr@3035fps
7th-Nosler#3- 55gr@3080fps
I hope this gives some insight as to variances that can occur between manuals. And even between lots of powder I would guess. Probably the biggest variable is the difference between rifles themselves.

NCsmitty
 
Hornady Rifle-Pistol Vol. II shows a max of 57.6gr. for the 130-grainer with IMR #4350. This manual was published before the Legal Dept. started peddling their paranoia in overdrive.
Click to expand...

I believe if you check the Hornady #3 the 130 gr SP turned into a "inner-loc" SP between the time of publishing the two.
The old load of 61gr of IMR4831 isn`t listed by anyone I aware of anymore either. Laywers aren`t always the reason for changes in data. New books are put out to reflect changes in components and improved test equipment.

BTW the Speer #14 lists 55gr of IMR4350 with their 130 gr bullet in the 270. Their old #10 has the same load as max. That 56gr load was only 1gr over book max. That kind of emphasises the truth in the warnings that one should start low and work up.....
 
Hi "Ol' Joe" -

I was wondering if perhaps IMR4350 had undergone some subtle change. Maybe - Maybe not. But whatever the reason for the changes - it sure sounds like I need to break down and shell out the $35 for the Hornady 7th edition.

Thanks !

:cool:
 
Being that the 3600 fps w/56 Gr H4350 and a 130 Gr bullet is so much out of whack with what others see, and published specs in 24" barrels, you would have to consider the readout an error or an anamoly.

The F1 Chrony folds open. If it wasn't completely open, the distance between the screens, (and the angle) would be off, causing it to read high.

With no disrespect to ants, you would have to discount that reading of one shot, suspect ants needs reading glasses, or that the chrony was in error.

I've got the Gamma Shooting chrony. If it is not fully open, the readings are way high. Even then, it isn't like a chrony can be 'calibrated' for accuracy.

But one thing is for sure, 3600-ish fps is far, far, faster than one can expect out of a .270 Win with a safe 130 Gr bullet load and a 24" barrel.
 
Hi ROA...

Thanks for the tips!

Everything I know about operating a chono wouldn't fill the primer pocket of a .22 Hornet so I couldn't even guess about an anomoly or a bad read or whatever else might have happened. But I figure the fact that new manuals stop short of that 56gr. load is probably a fair sign that it needs to be approached with a hatful of caution, if for no other reason than not scorching the BeJesus out of one's barrel.

:cool:
 
I agree!

A 130 grain bullet out of a .270 Winnie Pooh traveling 3600 fps out the muzzle seems a real "WOW" and impossible to duplicate safely. Recoil must be horrendous. While, a .243 Winnie Pooh gives an honest 3250 fps muzzle velocity with 90 grain premium fare without rattling my dentures loose. I've loaded 100 grain pills in .243 to plus 3300 fps, but that is admittedly insane, and NOT recommended. cliffy
 
ROA, you and I are thinking the same. It is not wise to draw a conclusion on one datum, so I offered no conclusion whatsoever. I suggested that Shawnee get access to a chrono and work on his loads. I was game to load a round and take a shot for the guy out of curiosity, but that's about all.

My chronograph is permanently mounted in the range behind the house. The screens are separated properly. And yes, I already wear reading glasses! I know you didn't intend any personal insults, you were brainstorming the possible sources of error.

Although I'm stationed 15 feet from the chrono and generally don't have a problem with hot blast, I suspect that this load discharged more hot gas than my normal loads. Those who understand the chronograph know that thermal ripples in the air above the electric eyes will distort data.
 
Regarding the anomoly with the "chrony".
This can happen too, if the chrony is set up too close to the muzzle of the firearm.

I've seen some bewildering results from chronographing my .300RemUltMag.
Like 3,600fps for a 180gr loading.
The .300RUM is HOT, but not that hot.

By moving the screens from 15', to 30', the anomolous readings went away.
I suspect that the .270 load in question did that.

Regarding the original posting, IMR4350 I suspect is a "tad" faster than it used to be, plus our newer pressure technology is much more accurate.

Jack O'Connor used to use 56.1gr (yes, the point one, is his doing!), and the Nosler, and other 130gr bullets. Remember this was long before the piezo-electric measuring equipment we have today. He also stressed the use of Winchester brass and Federal 210 primers.

The current powders at 54.0gr and a Hornady 130gr FB, gave me 3,060 from a friends Vanguard 24"bbl at 25'. or, about 3,100fps at the muzzle.
58.0gr of H4831 and 54.0gr of H414 were very similar. All gave sub-moa accuracy for 3-shots at 100yds.
 
While I don't know what velocity ant's 130gr .270 bullet flew at, I do know it wasn't anywhere's near 3600fps. If there's one thing I've learned about Chronys, it's that you can't have direct sunlight shining on the sensors. Direct sunlight on the sensors will give you readings of hundreds of fps faster than reality. On anything other than an overcast day, tape some translucent paper such as a large target to your two diffusers to block any direct sunlight from falling on the sensors.

Don
 
I have noticed with my Master F1 w/extension cable that although completely open on the tripod mount at first, tightening the screw down will cause the halves to slightly close at that time, or at some time during shooting. As mentioned, big time errors will result. Not sure if they changed the program or design of the sensors, but my first fixed display Chrony from 1993 seemed much more consistent, less sensitive to lighting conditions, and a much larger sweet spot over the sensors than my current one from around 1997?

What I did to help bright light performance was to enlarge the screens, using an old window washer jug and printer paper. Also use small wooden dowel rods instead of the steel ones provided.

IMG_8252.gif

Really thinking a CED or even a ProChrono's larger shooting area will help my aging eyes.
 
Status
Not open for further replies.
Back
Top