Why is my new 6.5 Creedmoor so slow?

[upSLIDEdown]

I posted on the 65Creedmoor forums, but thought I'd post this here as well, since I'm on this forum a lot more often.

**Cliff Notes at the bottom for the lazy ones... lol***

Just put a new gun together, Savage Axis with a 26" 6.5 Creed barrel from Apache Gun Works. Did a short break in on it as follows

Shot 1, cleaned
Shot 1, cleaned
Shot 1, cleaned
Shot 1, cleaned
Shot 1, cleaned

Shot 5, cleaned
Shot 5, cleaned

Shot 5 more to foul the barrel, and then did an OCW test.

Came up with the usual Creed load, ~41.7ish of H4350 behind a Berger 140 Hybrid. I decided to load 41.8gr of H4350, using BR2 primers, Hornady brass. 2.855OAL

I googled the load and most everyone running that load with a 26" barrel seemed to get 2800-2850fps. I used 2800 in my ballistic calculator.

Went to a match with nothing but a 100yd zero, hoping I'd hit something... lol

1st round hits at 450yds and 615yds, but after that, it started falling low.

After I was done, they let me fire a couple extra rounds at the 900yd plate, to see what it took to hit it, took 7.0 Mils. Putting that in, it gave me a velocity of 2700. Jeez. That's slow.

Picked up a chronograph to hopefully validate that. 2620fps avg. Wow. That's CREEPING. Went out to the place I shoot, used the 2620 in the app, and made good hits at 910yds and 1030yds. Dead on.

Granted, the match is at a higher elevation, so it could have been a little faster up there. My elevation is right around 850 and the match was at 2600. But still. Why am I so slow?

***Cliff Notes***
New gun
41.8gr H4350
Berger 140 Hybrid
BR2 primer
Hornady brass
2620fps.
OAL 2.855"

WHY?


Any thoughts?
Thanks in advance!

[sixonetonoffun]

I get 2785 average from 44gr of IMR4350 in my 260 with 20" barrel using Nosler brass and 129gr SST's. Maybe something closer to 43.5 would get you there. Giving 4831ssc a run for a hunting load next.

I'd imagine once ya are broke in or have hand lapped the barrel your fps will come up.

[darkker]

Oooff!
Several things here, so let's start with your assumptions.
Google brought up what people "say" they get for velocity. As the great philosopher Dr. Gregory House taught us: "Everybody lies". So based on that nugget, you assumed your own velocity... As you can see from the chrono, not so.

So "why"?
A quick glance to Hodgdon shows H4350 with a 140 class bullet having a MAX load of 40.0gr and 2660fps.
So here is where the default answers kick in. Never assume your barrel will be as fast as used in books, your components are not held to the same rigid specs. You have a different bullet. That may or may not have the same area rubbing on the bore, and may or may not have the same jacket material; again changing friction. There is no way of telling if you have the same lot of powder as tested. Hodgdon won't give any standard baseline specs for any powder, and we are the waste market anyway. So when things are different, they are different.

Not sure what app you have, but a good one will grab local elevation and climate to tell you exactly what is different. Personally I use Shooter, by Sean Kennedy. Some apps only use the single listed G1 coefficient, which also doesn't help.

The next question you have to ask yourself is, who cares? If you can reliably hit your intended target, does how fast you hit it matter?
I've got a great 308 load that I use out to a mile. Target impact is about 380fps, but I reliably cross trans sonic, so I don't care.

$0.02

[upSLIDEdown]

Fair enough. I get that people lie. I agree with that more than you know. I'd just like to think that considering almost everything I see says 2800, at least a few of them are being truthful. I dunno, that 2620 just seems awfully slow. I'd be a little happier if it was even 2700 or so.

In the grand scheme of things, I guess it really doesn't matter. We shot around 20 rounds at 910yds, and when we moved back to 1030, I plugged in the numbers and made a first round hit inside the 8" center of the target, and we both repeated it quite a few times. So yes, I'm hitting the target consistently. I'm not really sure how to describe what I feel, just really wish it was faster. That being said, I took the OCW test up to 42.9gr and still had no pressure signs, so hopefully there's another node up there that will get me where I want to be. I've got a big match coming up in less than 2 weeks though, so I guess I'm gonna stick with this for now and see how it goes.

I used to use the Strelok app. I DLed Shooter for the last match I went to a couple weeks ago, and I'm not sure if I'm just not used to it, but I like Strelok better. Strelok+ is what I was using this weekend and it gave me great results. I guess we'll see what happens. I appreciate the advice/insight. Keep it coming guys. I may just be disappointed for no reason, and if that's the case, then I'll just have to deal with it.

[Oxn316]

How many total rounds are down the barrel right now? I have a cbi barrel that sped up around 400 rounds. In my 260 i was at 2760 then sped up to 2807. Give the barrel some time it might speed up. My barrel is 26" also.

Also how big are the targets that your using to verrify your dope. For instance a 12"x12" target at 600 yards. Aiming at the middle of the target i could be a full minute off on my dope and still hit.

[SKami]

I've done a bit of load work with both IMR4831, and H4350, neither is at 2800, the IMR was in the 2670 range with a max charge, the 4350 is in the 2730-2750 range with 43+ grains! which is a bit above published max (this is with a .260rem by the way). Surprised me too, as many internet sources claim 2800+ with the same 26" barrel length. The 4350 is more accurate thru my rifle, and the Berger Long Range BT HP's are shooting to a POI that's 4 inches higher than any of the other bullets I tested, haven't chrono'd them yet, but I bet they are going a bit faster, as I doubt the significant POI change is due to BC's only at 100yrds. I'm no expert, so take this with a grain of salt.

[stomp442]

Also make sure to shoot through your chrony a few different times at different times of the day. Sometimes the sunlight can play games with those things and give you some whacky numbers. Your velocities do seem slow but if your hitting the target it doesn't really matter. A slow X is better than a fast miss.

[Oxn316]

I dont like using chronos. With my 260 with a brake i can get numbers from 2600 to 3100 in the same shot string. The brake really messes with it. I shoot 3" clay pigions ar 300 500 and 600 and use the the trueing in balistic ab program to get my final mv.

[upSLIDEdown]

How many total rounds are down the barrel right now? I have a cbi barrel that sped up around 400 rounds. In my 260 i was at 2760 then sped up to 2807. Give the barrel some time it might speed up. My barrel is 26" also.

Also how big are the targets that your using to verrify your dope. For instance a 12"x12" target at 600 yards. Aiming at the middle of the target i could be a full minute off on my dope and still hit.

Currently right at 100 I think. The target I was using this weekend is a 16" square with an 8" center. I was using the 8" center steel circle.


I've done a bit of load work with both IMR4831, and H4350, neither is at 2800, the IMR was in the 2670 range with a max charge, the 4350 is in the 2730-2750 range with 43+ grains! which is a bit above published max (this is with a .260rem by the way). Surprised me too, as many internet sources claim 2800+ with the same 26" barrel length. The 4350 is more accurate thru my rifle, and the Berger Long Range BT HP's are shooting to a POI that's 4 inches higher than any of the other bullets I tested, haven't chrono'd them yet, but I bet they are going a bit faster, as I doubt the significant POI change is due to BC's only at 100yrds. I'm no expert, so take this with a grain of salt.

Interesting...


Also make sure to shoot through your chrony a few different times at different times of the day. Sometimes the sunlight can play games with those things and give you some whacky numbers. Your velocities do seem slow but if your hitting the target it doesn't really matter. A slow X is better than a fast miss.

Good to know.

I dont like using chronos. With my 260 with a brake i can get numbers from 2600 to 3100 in the same shot string. The brake really messes with it. I shoot 3" clay pigions ar 300 500 and 600 and use the the trueing in balistic ab program to get my final mv.

Interesting you say that, since I'm also running a brake...

[Oxn316]

Keep shooting that same load and dont clean the barrel till accuracy falls off. Things will fall into place with it. Remeber speed is not everything.

[Oxn316]

Just looked up some average mv for factory creedmore ammo and 2700 for 24" barrels so 2740 for a 26". If your at 2700 your not far off.

[scope eye]

[QUOTE Remember speed is not everything.[/QUOTE]

Yes it is LOL

Signed
Incognito

[Oxn316]

Ugh scope eye your not helping.

[scope eye]

Seriously try some RL17 with the same load data as they H4350, you will be up at least 100 fps easy, with room to increase and without pressure signs.

Dean

PS: How did you know it was me.

[drybean]

My 27in CBI avg. 2825 fps
41.5 H4350, 140 Berger hydrid
oal 2.945, .010 off the lands

[drybean]

Maybe you goy a slow lot of powder

[upSLIDEdown]

Yes it is LOL

Signed
Incognito

Exactly.


Seriously try some RL17 with the same load data as they H4350, you will be up at least 100 fps easy, with room to increase and without pressure signs.

Dean

PS: How did you know it was me.

I have some to try. Just seems to be H4350 is more temp stable (supposedly).


My 27in CBI avg. 2825 fps
41.5 H4350, 140 Berger hydrid
oal 2.945, .010 off the lands

See what I mean? Dangit. I'm wondering if it's because I'm loading shorter to fit in the mag. Loading closer to the lands would increase pressure. I'm losing 2.855, and I THINK that was roughly .070" off the lands. I'll have to check that number to be sure.

[limige]

Keep in mind there are many people like myself included that are going off chrono readings. Which could easily be off. You drop tested yours so you have a better idea. I have not.

Now did you take temp humidity barometer and elevation all into account?
I understand its common for people who shoot 1000yrds matches to have different elevation dope from one comp to another. Due mostly to environmental differences.

Also keep in mind barrels are not perfect. A great gunsmith will spine the barrel so any runout results in the barrel pointed up vertically not down or to one side. If you had .001 taper downward it would require more elevation to get your bullet on target.

Dont get caught up in the numbers. If you wish search for a higher node if possible without pressure signs but if you loaded short to fit mag length I bet theres a big part of the puzzle. I saw over 60 fps drop in velocity back the bullet away from the rifling .060.

[limige]

Keep in mind a barrel will speed up as it gets fully broken in

[darkker]

Exactly.



I have some to try. Just seems to be H4350 is more temp stable (supposedly).



See what I mean? Dangit. I'm wondering if it's because I'm loading shorter to fit in the mag. Loading closer to the lands would increase pressure. I'm losing 2.855, and I THINK that was roughly .070" off the lands. I'll have to check that number to be sure.

Raising pressure is the only way to increase velocity.
Remember that the whole "idea" behind temp insensitivity, that property can only exist for a set of certain parameters; not a general property. There has been enough actual good testing by many, including Dr. Denton Bramwell that can easily be sought out. Varget as an example. Designed for the 308 with a 150gr. Bullet. Appears foot that billing quite nicely. Although folks will swear the same, Denton has shown it to be a streaming heap in the 223. Does that make it a "bad" choice for 223 loads? No, just means that the properties you bought it for may not apply, in that setting. H4350 appears to be designed around the 30-06 with 165gr. Bullets... Not exactly identical case as the Creedmoor.

As was suggested, you could have a slow lot of powder. I bought 16# of Win 760 a while back, it to is slower than suggested. I have a load within current Hodgdon data, that does a 10-shot average of 2725fps @ 15 yards.

As for the "no signs of pressure" do whatever you wish, but keep in mind the truth about that. Compared to nothing: measuring case expansion is better, judging bolt lift is better, staring at primers is better.... However:
For the 50,000+ psi range cartridges VERY carefully calibrated copper crushers have been repeatedly proven to not accurately report pressure. To the tune of 5-7,000 psi variations, that is why piezoelectric/strain gauges are used.
Very uncalibrated cases & primers aren't going to be better judges of actual pressure. There is no single formula for cartridge brass. IF one could only build following the handbook for metals, the tensile strength for cartridge brass is @ 70,000 psi. So when you see growth and stretching, well you know what psi range you are touching.