Velocity Questions

[TD-Max]

I have a question regarding velocity. I realize that accuracy is more important than velocity in most cases, but I've been puzzled with my findings. I also realize that powder can vary from lot to lot and barrel length is said to have some effect, but I believe I read it to be quite insignificant with the 204.

I have a PACT professional chrono and have been doing loads for both a Howa 1500 22-250 and my Sako 204. The issue is that my speeds are not on par with what the data sheets publish. I though it may be the chrono, but I used Remington UMC for foulers in my 22-250 and these did indeed clock at 4,000fps. I plan to clock some factory Hornady 32's also.

I am using the RCBS Chargemaster 1500 w/o a backup scale. Brass is new and trimmed, chamfered, uniformed, deburred etc. Bullets are seated out past magazine length and hand fed.

Here's a few examples. Speeds are averages and ES varies from single digits to 80's:

204:
IMR 4895 with 39BK

27.4 clocks @ 3560 best group by obvious margin all touch
27.6 clocks @ 3587 fps
27.8 clocks @ 3641
Sierra says 27.5 (their max) should be at 3700fps.

Re10x with 32BK

26.0 @ 3848
26.2 @ 3883 best group by obvious margin all touch
26.4 @ 3933
26.6 @ 3958
Sierra says 26.3 (their max) should be at 4,000fps and Rick in Oregon has reported 26.5 @ 4,000fps

Benchmark with 32 BK

27.3 @ 3707
27.5 @ 3743
27.7 @ 3794 best group by narrow margin
27.9 @ 3817
Sierra says 27.9 (their max) should be at 4,000fps


22-250:
Rel 15 with 50BK

35.9 @ 3641
36.1 @ 3721
36.3 @ 3713?
Sierra says 36.0 (their max) should be at 3700 which matches my findings


IMR4895 with 50 BK:

35.9 @ 3595
36.1 @ 3607
36.3 @ 3603?
Sierra says 35.9 (their max) should be 3800

Varget with 40 Nosler

34.8 @ 3458
35.0 @ 3514
35.2 @ 3497?

Nosler says 34.0 should be at 3625

None of the 22-250's grouped particularly well.

I do recall loading 1.990 comparator versus 2.060 comparator with teh 204 and seeing the 2.060 clock about 100fps slower I lost the chrono that day due to sun, but seem to remember this.

So seeing that some match and others don't should I start to push up the charges incrementally? variations of powder lot to lot? I haven't seen any signs of issues except one day (no chrono) when I ran the 39 BK with 27.3 and more Benchmark and started to see cratering.

P.S. This data was from a quite clear and sunny evening which may account for some of the ES, but the "slowness" is something that I have seen quite consistently. All loads with CCI magnum primers.

[Rugerdogdog]

What length is your barrel? I've not read that barrel length is insignificant in the 204. There is an article on the home page that says, if my memory serves, that there is no significant gain after 26". But I do remember that Sierras info is gleaned from a 26" barrel. Your info seems to be right on par for a 24incher?

[Hotshot]

First step should be to test with a different chronograph. Second step don't judge the safety of your loads by somebodies printed data. Most of us choose our varmint cartridges for high performance and we tend to hotrod a little bit, well maybe quite a bit. Be carefull, be safe, and watch for pressure signs NOT velocity on a chronograph.

All that preachin' aside, I do think your readings are quite low, I've used similar loads in 204 and 22-250 that read higher on my chrony. I've checked the chrony against an expensive Oehler and it was very close.
Maybe the manufacturer would check and re-calibrate for you.

[jo191145]

Maybe do away with the magnum primers. Seldom used them enough to offer an opinion but never found a reason to continue their use. I'm about to load tomorrows fodder now. I'll throw in a few CCI mags and check the velocity's.
You do have the short barrel and are increasing the volume by loading further out. Nonetheless your velocity's sound low. Not shooting moly are you

As Hotshot stated. Take published data with a grain of salt. Compare a few different loading manuals and a couple different burn rate charts and that will hammer it home fast.

[glenn asher]

My little CZ has a 21.9" barrel,( according to them), and runs roughly 250fps slower than my Savage 26" barrel. There can be significant velocity loss with a shorter pipe. I was surprised it was that much, to tell the truth, but no matter, it still kills stuff.

Considering the speeds your .22/250 loads are quoting, I would want to get that chronograph checked and calibrated, I've shot some of those same loads in three different .22/250s and all were a LOT faster than what your chronograph is saying.

[Glen]

A chronograph is a valuable tool for reloading. When you reach the "land of diminishing returns" for a .xxgrs increase & the velocity is not jumping accordingly you are getting into an area you don't want to be in.

Example. If each .2grs is averaging 100fps increase then suddenly you're only getting 50fps per .2grs,, you are heading for a nasty pressure sign.

Please Be Careful. You may only get 1 chance. The lucky fellas get 2.

[TD-Max]

back at it again today:

204

32BK Rel 10x 26.2 3873

39BK Rel 10x 26 3776


22-250 50 BK

36.0 IMR 4895 3661
36.5 IMR 4895 3712

35.7 H4895 3665
36.2 H4895 3725

32 Rel10x 3678


Just to prove it can do 4,000+

40 BK

Re10x 34.5(max) 4065
Re1ox 34.7 4116
Re10x 35 4157

[acloco]

Try some Fed 205M primers, but work the loads up, don't just swap the primers and go.

[TD-Max]

Will try the Fed 205's

Just looking over the targets here and maybe I'm being overly critical of the Howa. The Sako 204 can reliably put 5 shot groups together that will cover with a dime.

The Howa has done some nickel and dime size groups, BUT is almost always plagued by a single flyer often 3/4 to 1" away from the rest. My H4895 35.7gr 4 shot group is easily sub .300 but I have a single shot off about an inch. The IMR4895 almost covers with a nickel and clocks similarly.

[TD-Max]

I can shoot 5 inside a dime very consistently with my 204 now. Pretty decent groups, and seldom any bad fliers. The 22-250 is more like a nickel with the best load, but is frequently plagued by flyers 3/4 to 1" away. Looking to pick up a manual powder scale to cross check my RCBS chargemaster. Only thing is, it takes a full .5gr charge change to get 50-100fps average so my loads would have to be WAY off to see this much swing. Might be the chrono? But then factory ammo seems pretty consistent usually within 40fps or so. Must be something with my loads and/or loading?

Just running down the line on the ES side here's some examples:

22-250:

44.1 Rem UMC 45 gr at 3905 Av freshly cleaned barrel
117.6
73.2
127.1 35 Rel10x 40BK 4133fps 4 under a dime with one flier .5" high and right. If I take out the one fast shot (not sure where it landed in the group) I get ES of 50 over 3 shots. I missed on with the chrono. This load is over max
87.9
31.8 36 Rel 15 50BK 3637fps 4 easily under a nickel with one flier 1" left
85.3
94.5 36 IMR 4895 50BK 3661fps 5 almost under a nickel
41.5
72.2 35.7 H4895 50 BK 3665fps 4 under a dime one flyer 1" right
21.8 36.2 H4895 50BK 3725FPS 4 almost under a dime 1 flyer .5 left


204:

73.4 Factory Amer Ammo junk at 3027 FPS av 39BK 3 rds used after horough cleaning
67.1 26.2 Rel 10x 32 BK 3873fps almost under a nickle usually groups better maybe needed more rounds after cleaning?
37.8 26gr Rel10x 39 BK 3776fps groups under a dime- my best load
36 Factory 204 Win 32 gr at 3961av

Forster Co-ax press. Forster Bench Rest full length sizer die. Forster micrometer seater. RCBS trim Pro with single cutter (3 way leaves scratches in neck) and RCBS Trim Mate for primer pockets, chamferring, flash hole etc all work performed extremely consistently and brass grouped by weight.