My velocity seems to be off?

[DalesCarpentry]

I have worked a very accurate load for my Remington 700 VLS 308 with a 1 in 12" twist barrel. The barrel is also 26" long. If I do my part I can shoot one ragged hole at 100 yards with this load. The load is Remington brass, 165 grain Sierra Spitzer boat tail Game King bullets part number 2145, 44.0 grains of Varget and CCI 200 large rifle primers. Looking through several load books I figured my velocity to be around 2725 FPS with my 26" barrel. Well I was out at the range a few weeks ago and a buddy of mine was there with his chronograph and I asked him if I could run a few bullets through it to see what velocity they were running. Here are the results. First shot 2577 FPS, second shot, 2588 FPS, third shot 2587, and the final shot 2555 FPS. That gives me an average of 2576.75 FPS. Does this seem right to you guys? It seems to be much slower that I would have thought it to be especially seeing I have a 26" barrel. I really have no experince with chronographs and is such a variation in bullets speeds normal? What is a normal variation? Thanks and take care Dale

[gypsyman]

Dale, don't worry about the difference. As far as what you expected, your 125 fps slower readings are in the ballpark. I havn't heard of very many people actually getting what the books tell you.
You had a 33 fps difference in a couple shots. That very well could have been the difference in primer charge's, and nothing you could do about it. As long as the gun is shooting good groups with that load, keep using it. gypsyman

[Dand]

While I have seen better consistency sometimes,  I've also seen MUCH worse variation probably more often.  I'd say you're probably getting good accuracy in part due to the reasonably moderate variation. I too rarely get the speed the books claim for my 30-06. On my 300 win mag I get the speed or even better, sometimes, but not always. There also is the minor difference in the "instrumental velocity" (the midpoint of the chrono screens) vs calculated muzzle velocity that may be 3  to 10 feet closer to the gun than the instrumental velocity.  If you're getting good accuracy and case life don't worry 'bout it. If you need more velocity and there is room to work up safely - try it out.  Good luck.

[1sourdough]

 With a 165 grn bullet out of a 308 that sounds about right. I think more reloaders would question their loads if they were able to use a crony more often. You could work the load up some if you have room on the top side of the data. The other option is to try a faster powder(H-4895/TAC). Of course if their shooting great for you & you put the bullet where it needs to go you don't have to do a thing.

[Lloyd Smale]

what kind of chrongraph. If its a crony ive seen them vary up to 200 fps between units.

[wncchester]

"I figured my velocity to be around 2725 FPS with my 26" barrel. ... That gives me an average of 2576.75 FPS. Does this seem right to you guys?"

Well, if I figured my velocity to be one thing and a chronograph said another I would suspect the chronograph was closer to right.  ??

[drdougrx]

OOOOWWWWWWW.....the evils of Chronography!!!!!

Dale...I know what'cha mean!!!  FWIW....My Sako in 06 with a 22" barrel was giving me 1" groups and a velocity of 2650 with 165gr bullets.  Now I'm working up new loads for higher velocity.....why???  Cause I can......not that any animal will ever know the difference!  Drives me... and now you... crazy!  Ain't it fun.....  whooooppppeeeee........

[Catfish]

Dale, You have just learned the first lesson with cronographs, they tell you nothing about how your gun is shooting, but can make you doubt your gun will shoot at all when you just put 5 shots in the same hole at 100 yrds. To measure the difference in velocitis between round we use a term Standard Devation or SD. The lower the SD the better you would think a gun would group. Some times that is true, but out to 250 yrds or so with center fire rifles, I have seen bug hole groups shot with a laod with a SD of near 50 and shotgun like patterns fired with loads with a SD of 7. SD does get more critical when you you start shoot longer ranges. Past 500 yrds. the difference in velocity will show up in vertical stringing. You already know that barrel lenth effects velocity, but I have compaired load to what the book said I should get and while they are usually close I have seen them both alot higher and a lot lower than what the book said. Crono`s do a real good job of compairing velocities and get you what you need to work up a drop chart but not alot more.

[simplicity]

I've exsperienced really similar problems once I started chrono'ing all my loads. I've found with most rifle loads in "new " loading manuals according to my chrono I usually get 200-300 fps what the book claims me to be getting. The other thing is I have learned to use older loading manuals (1980 or older) I've found pretty much accrosed the board with the older manuals that the velocity specified is pretty damned close to what your going to get but also if you compare the data the older data is pretty much always been a few grains more.  I honestly think this is just mostly due to reloading manuals "insurance policies" As far as the spread usually +/- 20fps is quite normal

[MePlat]

Message body is empty

[SHOOTALL]

Was it cold when you clocked the load ? I have had loads that were fine in winter and a bit hot in 100 degree heat. Check them in aughust if you are looking for max vel. Of course some powders display this trait more than others.

[Stillkickin]

Your results seem to be right in line with mine on a very similar load.  From a 22" barrel Remington 700 .308 with 168 grain Nosler ballistic tips, 43 grains of Varget produced a three shot one hole group at 100 yards and an average velocity of 2556.  The last three deer shot with that load dropped on the spot.  I wouldn't consider your load to be off at all.

[DalesCarpentry]

what kind of chrongraph. If its a crony ive seen them vary up to 200 fps between units.

Yes Loyd that was the brand of it.

Was it cold when you clocked the load ? I have had loads that were fine in winter and a bit hot in 100 degree heat. Check them in aughust if you are looking for max vel. Of course some powders display this trait more than others.

Shootall yes it was cold about 30 degrees or so. I am using Varget and it is one of their extreme powders. According to them the temp should not make a difference. I have no idea if that is true or not. I do know that buying a chronograph is on my short list of must have reloading items. I will not be buying a Chrony though. I have heard of some bad reviews of them. Midway has one that I want to get and it does not cost to much more and the reviews of that one are pretty good. I just can't remember the brand name of it off the top of my head rite now. I may try to work up a load with a higher velocity come spring time. I would not mind getting another 100 FPS out of it if I can do it safely and get it to shoot tight groups. With me accuracy is more important that anything else. What chrnograph do you guys feel is the best for the money. I don't need a fancy one with a printer. I just need one that does what it is suposed to do and do it consistently. Thanks and take care Dale

[Slufoot]

Hey Dale, I've had a Competition Electronics chronograph for several years and it has served me well. They aren't much more if any then the Chrony's.
I once took the LED display out with a sabot from a muzzleloader, Competition Electronics replaced the LED display and calibrated my chronograph for a very small fee. I then made a guard to keep stray sabots from hitting the display screen. I believe they are a good company to deal with.

GOOD SHOOTING!
Slufoot

[SHOOTALL]

The brand I use is OP , other peoples