Whoa!

C

Chainsaw.

New member
So Ive been loading my 255 grain cast keith style bullets over 8.3 grains of titegroup which per the lyman book should net ~875-900 fps. Well a friend brought his chrono to the range the other day to let me test a few loads, turns out Im getting 1050 fps:eek: Not necessarily a bad thing but but holy baloney! Book used a 4" test barrel, Im shooting a 5".

Good news is my magnums are coming in about 1250.
 
if you are getting over 10% excess velocity it might also mean that you are getting higher pressures. Maybe MUCH higher pressures. An extra inch shouldn't cause that sort of increase. Let other people advise you, but I'm concerned.
 
Was it bright outside with the sun shining on the chronograph? My 1000fps loads will read 1400-1450fps if it's super bright out.learned real quick to wait for the cloud coverage.
 
9miller. No, it was over cast an amongst tall fir trees. One addition to the info, they are powdercoated bullets...?:confused:

Nick cs. 44mag
 
"Was it bright outside with the sun shining on the chronograph?"

It is not the sun shining on the chronograph, but it might be the temperature of the ammunition. Hot weather can cause increased pressure, whether the sun is shining on the chronograph or not. That is one reason not to load to the book maximum in the summer; the additional heat can push pressures into the dangerous range.

Jim
 
Getty-up

So Ive been loading my 255 grain cast keith style bullets over 8.3 grains of titegroup which per the lyman book should net ~875-900 fps. Well a friend brought his chrono to the range the other day to let me test a few loads, turns out Im getting 1050 fps Not necessarily a bad thing but but holy baloney! Book used a 4" test barrel, Im shooting a 5".

Good news is my magnums are coming in about 1250.
Click to expand...

You are shooting lead; what if the diameter of the bullet was .001" larger in diameter and required more pressure to force it down the barrel, my opinion? That would speed things up. As opposed to shooting loose bullets?

And then there was this shooter that took two coronagraphs to the range and could not get them to agree. I suggested he pop the hood and check for a an adjustable pot or rheostat or check with the manufacturer to see if they had a two for one deal on calibrating chronographs.

And then it was suggested the shooter set up a portable tent over his chronograph.

I was thinking placing chronographs in series was a bad habit; there are shooters that have shot their chronographs, in series it is possible to shoot two of them.

F. Guffey
 
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Obviously you need your very own chronograph.
Reloading data from web sites and books are just guides.
Not necessarily what anyone will actually get from their own equipment, as you have seen.
 
If you have the cash available, wait for one of the Midway coupons to come up and get a Labradar from them. It uses Doppler radar, sits on the bench next to the gun barrel, so there's no setup time beyond plunking it down and turning it on (1< 1 minute?) and it doesn't give a rat's backside what the sun is doing, and is, as near as I can tell, typically at least as accurate as the 0.1% they advertise. It can, occasionally have a reading error, but no more than optical units do.

If you want zero reading errors, the Magnetospeed is another non-optical that seems to have high accuracy, plus it costs a little less. I went with the Labradar because I didn't want a "tuning" weight hanging off my rifle muzzles and interfering with an accuracy test string. I also don't have rails on my pistols to mount the Magnetospeed, but on a revolver there's no moving slide to create a problem.

Regarding actual velocity, your extra barrel should add about 33 fps to velocity as compared to the SAAMI standard 4" revolver test barrel with 0.010" barrel/cylinder gap emulation. If your existing set of readings are accurate, you have more pressure than advertised. One thing that can cause that, in addition to you using a different lubrication, is different powder space in the case due to different seating depth. Do you know for sure your bullet is not longer than the Lyman bullet used in their data. If you have less powder space, you will get higher pressure.

Seating Depth = case length + bullet length – COL
 
That Im sure of. Im using a lyman mould and the specs out of the book for that exact mould. Seating at the crimp groove.
 
I'm running an RCBS 45-270 (265 actual/#2) over 8.1gr TiteGroup in a 4-5/8" New Vaquero for 920fps (Oehler'd).

Your velocities are consistent with that same result.
 
One addition to the info, they are powdercoated bullets...?
Click to expand...
That very well might be part of your variance.
I've noticed higher speeds from powdercoated bullets vs otherwise identical bullets with conventional lubes. I believe the guys over at cast boolits have documented this.
In my cowboy loads, the added efficiency is actually nice, as I can download a bit vs my old lubed data with no harm. In .300 Blackout subsonic loads with a narrow window for proper cycling in an AR even with regular lubed lead, it's downright inconvenient.
 
Poodleshooter, very interesting, I had not heard of this phenomenon. Between that, an extra inch of barrel and a slight bump in powder I guess I'm no so far out of spec.

Maybe Ill back er down a bit to make them a little more peasant.

Thanks guys. :cool:
 
I think y'all are wasting your Titegroup when you load it that heavy. If you want more velocity, use a more appropriate powder. Titegroup is a great powder for standard velocity target ammo. I use it in 45 Colt at 6.2 grains that with 255 grain cast bullets yields a very accurate 840 fps in my Vaquero. In the 44 Magnum, typical 240 grain bullets will achieve similar results using 5.5 grains of Titegroup. Not true Magnum loads, on the contrary, these are excellent target and practice loads that take the Magnum down to 44 Special equivalent performance. Don't look at it like you are, "castrating", your Magnum, but rather that it's a super-accurate practice round that you can shoot all day long without recoil-fatigue.
 
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