Home Forums Reloading Big Game Rifles Slow Chrono Reading for .280 Rem

Shooting a 140 gr. BST over 56gr. RL 19 and a WLR primer from a 24" barrel at 2200' above sea level. My chrono gives me 2717 fps. This seems pretty slow. Anyone have any ideas?

Have you chrono'd other loads and how many rounds gave you the 2700 fps and what was average, as well as other readings that chrono gave. How were groups? Have you chrono'd factory 140 loads?

Have you tried other powders and other bullets?

Rl 19 has never given me advertised velocities in the .280, nor has RL 22. With 140-grain bullets, I prefer IMR-4350. For 150s and 154s, I prefer IMR-4831, and with the 160-162s, IMR-7828.

I've never gotten advertised velocity out of RL-19 either. I can't say about it in the .280 since I don't have one, but for the rounds I have tried RL-19 in I have been disappointed.

That was the average of 5 rounds. The load shoots one hole at 100 yds. so I'm pretty happy with the accuracy. Just surprised at the lack of velocity. Never chrono'd a factory load. Readings were all within a few fps of each other.

Ranger1, how familar are you with the rifle in question? Has it exhibited "slowness" before? Have you used the R19 in it before?

I have a 270 Win that just gives slow speeds with 4831, and I need to stoke it up with more powder to get book maxes. It took me a while to work this out. This included shooting factory ammo through it too, and finding out that factory rounds were also well below advertised.

Kinda worked out that I have a chamber and barrel that generates lower pressure and I need a little more powder, especially in the case of 4831. In the end I pushed 3g beyond the Hodgdon/ADI max, but there was no indication this was a hot load, either with empty cases, the chrono or elsewhere.

I always go through a short re-test with these loads when I change powder lots, because powder lot consistency can fudge things up too.

Sorry if my post seems to be telling you something that's obvious. But I would advise trying a different powder if you have it or maybe trying with great care, a little more powder.

Try some IMR4831,it appears to be one of the best powders in my 280 Rem.

RL19 & RL22 are very good performers too.


These are some chronographed results (5 shot average) from my Ruger M77 .280 22"bbl



140gn Nosler Accubond

57.0gns RL19.......2903fps
58.5gns RL22.......2933fps
56.0gns IMR4831....2935fps

140gn Sierra Spitzer

53.5gns H4350......2838fps
53.5gns IMR4350....2768fps

Yes. RL 22 and add more powder...you should be over 3000 fps and I doubt you will see any issues.At least I have not from more than a couple of 280's.

Use Fed 215 primers and work up from below.

Years ago I had worked up to a load in my 22 inch barreled .280 with 56 gr. of imr4831 with a 160 gr. speer spitzer, R-P cases, cci 200 caps.

The load kilt game like a hot bolt of lightning, especially elk it seemed like and clustered shots right into an inch @100 yards... It was a warm load and I just KNEW it had to be in the high 2900 fps range, This was in my pre-chonograph years of reloading.

Then I acquired a chronograph........

Velocity was exactly what the speer no.10 manual says 55 gr. of the said powder would do in a 24 inch tube 280 rem, 2893 fps.

I then soon found that grains of powder vs. velocity was almost a complete crapshoot in many rifle/calibers. So much so, I double check couple different load charge weights on a different scales, at most there was a .2 grain difference, But velocity said different.

I tried some rl 19 with 140 nosler partitions. Accuracy was ho-hum for all loads but it was not till I hit 57 grains of rl 19 I broke 2900 fps. Pressure signs at 59 grains and 3028 fps I quit with rl 19.

Ended up with imr 4350-56 gr. and 2970 fps with the 140 partitions. inch clusters @ 100 yards. This load Would BLOW down mule deer and whitetail several times for me.

Add more powder and use your chono. Take heed to pressure signs such as hard extraction, shiny ejector marks, way flattened primers, loose primer pockets.

Bet your chrony is right...

Ranger, I load 56 or 56.5 of RL19 in my 7x57AI which is basically a 280. I get over 3000fps w/the 140gr BT. RL19 varies quite a bit from lot to lot so the difference in starting charges. If I couldn't get RL19 to shoot well I'd try IMR4350 next then try 4831 next. Don't be afraid to go up a few grains w/each powder watching for pressure signs. I know it's frustrating cause I have a 338-06 that won't come within 100fps of book velocities w/180gr bullets. Good luck, cause the old 280 is a very worthy cartridge. powdr

Nate-I'd give it a try another day just to see if the reading stays true.

Dober

On the .270 Win. comment.

"This included shooting factory ammo through it too, and finding out that factory rounds were also well below advertised."

I noticed this as well and I have to wonder just when it came about. Could it be that full power .270 ammo turned out to be a bit much for the Remington pumps and various companies autoloaders? Just a thought that crossed my mind as you do see to not load hot with heavy bullets and slow powders in autoloaders. but then, what do I know?
Paul B.

Paul B, for what my knowledge is worth...

I think I read in a magazine quite a few years ago that ammo makers started loading 130g 270 ammo slower, because too many hunters complained of ruined deer meat.

However that does not explain why the Win 130 Powerpoints which are advertised at 3060fps, shot only about 2900-2920fps in my rifle with 24 inch barrel, in a series of range sessions in different temps and light conditions.

I once owned a .30-06 with a 'slow' barrel... Loads from every manual, along with factory ammo, failed to get anywhere near the suggested values- some by more than 300 fps. I wanted more... I found W760, and an older Hornady manual got me closer. A rifleman friend explained it as suggested above. If you are not getting the velocities, you are probably not getting the pressures either. I had the barrel and chamber carefully inspected. The excess freebore, throat erosion and a bore on the large side of the tolerance resulted in a rebarrel.
Voila! Book values at last. Only took about 4000 rounds...
YMMV

Last year, Federal Blue Box 130's gave 3106 from the 22" barrel of one of my 270 FW's.It isn't all loaded wimpy...but no doubt some is.

Similar result for the cheap Federal blue box 130's.
I was consistently over 3200 with my 24" tubed KS.

Shot accurately too.
Don't know why I even bothered to reload that one.
But I did.

I appreciate all of the advice. My experience with chronos is a little limited. If I shoot on a sunny day, am I correct that I will likely get skewed readings? If this is the case would setting a small awning tent over the chrono fix this problem when shooting on very bright days? The gun range is under a few feet of snow right now so I won't be out doing any shooting in the near future, but as soon as the snow melts enough to get in there I hope to try to figure out what is going on with this round. It was very bright and sunny when I shot these loads over the chrono the first time.

If you can find someone who will open their vault and trade you a round of .22 LR for your house, vehicle, or first-born child, check the advertised velocity for that round, and shoot it across the chrono, it should give you a really good idea if your readings are accurate.

I keep hearing this myth that the way you test a chronograph is to shoot commercial 22 LR over it can compare the results with advertised velocities.

Here's a sample of 4 .22 shot over a chronograph with Remington Yellow Jackets. Advertised velocity is 1500 fps:



You will notice they have a large variation between guns, high standard deviations, and none of the results approach the advertised velocity.

.22 are just like any other ammo, change the firearm, or temperature, and the velocity may vary....but then again, if velocity did not vary there would be no reason to own a chronorgaph.