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There is a direct relationship between pressure and velocity in cartridges. THe higher the pressure the higher the velocity. The 6.5 Creedmore is a real pressure pot, because many think that velocity is king and they are trying to turn an accurate fun to shoot cartridge into a 264 Win Mag. It doesn't need to go that fast. The incredible ballistic coefficient of those long bullets will take care of the drop making it easier to hit targets at unknown ranges. I have one of Savages early 6.5Cs. and I get cratered flat primers from even factory brass. This should tell you something. Everybody loads that round way to hot. In fact they are loading it so hot that it is starting to get a reputation of having bad bullets. It's the same problem the early "Magnums" had, people took the same bullets they would load in their 06, or 270 and rant them 200 to 400 fps faster than they were designed for.

You might find some relief by cleaning the rifle often. The long throat of that round will collect powder fowling and make the pressures rise. As another member said: "Look to the bright side and just load the round with less powder (let your Chrony be your guide) get more loads from a pound of powder and have an accurate barrel longer.
 

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Discussion Starter #22
I think what I'll do is walk away from using the hybrid and superform. Those two powders are to close to the ragged edge for for my liking. At least in my gun. I can go back to the drawing board with h4350. Had one node down on the bottom with that powder that showed some potential but I didn't care for the annoying little flyers it was giving me.
 

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Elk Whisperer (Super Moderator)
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H4350 hits a point where it does the same thing. ** At 43.2 your happy was can be, then at 43.3, your bolt is stuck.

"DAD!!?"

" What? "

"Something is wrong with my rifle!!" No, not my son, my Dad's son :D

RJ

** Just numbers for explanation purposes, not actual factual weights
 
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Maybe you should make some chamber castings. Compare dimensions of problem rifle against a rifle with no problems. Savage might make it right if the chamber was cut too short or small. Worth a try.
I am the only reloader that can cast a chamber; the rest just go through the motion of chamber casting.

F. Guffey
 

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Discussion Starter #25
Well, went back to the H4350. Backing off Hornady's starting load a 10th gn tamed the flyer for me. Still getting crazy speed numbers. My little pressure cooker is squirting out 130 ELDs 250 FPS faster then start loads. Three shots through my chrony were 2873, 2851 and 2860 FPS. SD of 11.04. I guess I'll see how many rounds I get on a case before the primer pocket stretches out or I gotta do a shoulder bump. I got two firings on these test cases with no trouble so far.
 

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Discussion Starter #26
Junior just shot that same load in his 12fv with his cases. The chrony said his three shots were 2819, 2793 and 2811 FPS with a SD of 12.68. I'm starting to think Hornady load data is off or my chrony is a liar.
 

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The Shadow
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All chrono's that I've used/seen have their own set of "quirks" from time to time. A good example is something funny in Phoenix. My chrono seems to be as stable as can be here, magically once down south, the sun does some funny stuff.....

Also in several chamberings over the years, Hornady's claims tended to range from ......Ambitious, to flat pipe dreams. YMMV



Cheers
 

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Discussion Starter #28
I think my chrony is pretty darn close Darker. Hornady ballistic app says to come up 9.82MOA at 500 yards so we did ( 9.75"). My group is on the left. I think Hornady's load data is off. I'll get a better idea whats going on when the x-bolt gets back here. That's a 2" bull BTW.
 

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Junior just shot that same load in his 12fv with his cases. The chrony said his three shots were 2819, 2793 and 2811 FPS with a SD of 12.68. I'm starting to think Hornady load data is off or my chrony is a liar.

Doesn't sound that way to me. Sounds like two different rifles complete with different actions and barrels!
 

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Discussion Starter #30
Both are Savage model 12 fv bought from Cabela's two days apart. We also have the same scope, rings and base. The only dif is I put a Boyds stock on Junior's (future SIL) rifle.
 

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The Shadow
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But to be fair, MZ5 and I bought twin Ruger Predators from the same store, at the same time... Except he writes slow and took longer:D. The serial numbers are within a dozen of one another. Different amount of freebore, different bores. Regardless of which of us shoots what, his rifle never was as accurate as mine.
 
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Elk Whisperer (Super Moderator)
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Discussion Starter #34
If Don is referring to difference between Hornady's test rifle and ours, then yes, I agree as well. I just can't get my head around the velocities we are getting. In thirty five years of reloading I don't ever recall working a load down from minimum.
 

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The Shadow
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I just can't get my head around the velocities we are getting. In thirty five years of reloading I don't ever recall working a load down from minimum.
It's not so difficult, imagine the following reasonable scenario.

Savage has a.... generous..... Tolerance from specs on a new reamer to an old one. Rifle #45 is the last of the old worn out reamer, #46 is the shiny new reamer. You get #45, your buddy #46. Your lot of powder, by chance is similar to the burning rate of the lot (which wasn't stated) tested in your manual. Your buddies powder is from a totally different supplier because Hodgdon for a better deal while GD was redoing the plant in Quebec. So even though the name on the bottle is the same, the powders are different.

Sometimes that's how life is.


Cheers
 

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I think my chrony is pretty darn close Darker. Hornady ballistic app says to come up 9.82MOA at 500 yards so we did ( 9.75"). My group is on the left. I think Hornady's load data is off. I'll get a better idea whats going on when the x-bolt gets back here. That's a 2" bull BTW.
I have always heard to test a chronograph against 22 rimfire ammunition, as you should get pretty close to the published velocity from most any rifle.
 
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It's common to need to be 0.030" off the lands to avoid pressure going up a little. Contact with lands typically raises it 20%, but it's not a sudden jump. The increase happens over a range as you get close to the throat, so you might be in the range of about a 7% increase where you have the bullet.

You appear to have what is affectionately referred to as a fast barrel. Have you slugged your barrel? A tight bore can cause this. Slug from the muzzle with a pure lead bullet or ball or fishing sinker and feel for any constrictions, especially where the barrel contour gets thicker. Such a constriction may not affect accuracy but will need to be firelapped out to get more normal pressure from commercial loads and the like. Your barrel is 26", where the SAAMI pressure and velocity test barrel used by Hodgdon and commercial ammunition makers is 24" in 6.5 Creedmoor, so you can expect your barrel would produce about 2% higher velocity even if every other dimension were identical.

Note that copper fouling build-up can cause a constriction you feel slugging the bore, too. If you don't have a borescope to check for that, having had a Savage barrel that copper fouled badly and fast (in just ten rounds, accuracy was diminishing), I can tell you that putting in a chamber plug and flooding the breech end with KG-12 for half an hour may well be your best bet. Bore Tech Cu++ also works well, but expect to leave it for an hour or two. The advantage to Cu++ is it turns blue, so you know you got copper out, where KG-12 goes from tan to an orange-ish tan, so even though it eats more copper faster than any other copper cleaner I've ever tried, it gives you little indication of what it has done.

The average pressure on the base of the bullet during its trip down the tube is proportional to the square of the velocity. The KE of the bullet divided by the length of the bullet travel in feet is the average force in pounds that pushed the bullet forward. Divide that force in pounds by the cross-sectional area of the bore, and you have average pressure. Average, though, not peak. The average pressure is between the peak and the muzzle pressure. However, since most of the powder is burned by the time the bullet exits, you can assume your muzzle pressure is about the same in all guns with the same barrel length firing the same load. Velocity differences will come from peak pressure variation, primarily.

I have been working on a method of estimating peak pressure from published pressure and velocity data like Hodgdon's. I have it in an Excel file, and while I don't yet consider it safe to release, if I read your data correctly for the right bullets, this is what it is coming up with currently:





The PU in this case are psi, because that's what Hodgdon's data was measured in.
 

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Discussion Starter #38
It's not so difficult, imagine the following reasonable scenario.

Savage has a.... generous..... Tolerance from specs on a new reamer to an old one. Rifle #45 is the last of the old worn out reamer, #46 is the shiny new reamer. You get #45, your buddy #46. Your lot of powder, by chance is similar to the burning rate of the lot (which wasn't stated) tested in your manual. Your buddies powder is from a totally different supplier because Hodgdon for a better deal while GD was redoing the plant in Quebec. So even though the name on the bottle is the same, the powders are different.

Sometimes that's how life is.


Cheers
That's easy enough to under stand Darker, thanks. Even though Junior and I are using powder from the same jug and the same bullets from the same box and the same primer we are going to have different results then Hornady has published in the manual because of their lot of powder used.:cool: The reamer thing I pretty much had figured out. Now I am really curious to see what that other savage 12fv has to say when it gets here.
 

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Discussion Starter #39
Thanks Unclenick, that makes sense as well. We are both at the same OCL but Junior's round is a lot farther off the lands then what I am. Between the tighter chamber plus the difference of bullet to lands explains the 50 FPS or so difference in our velocities. Should have a real good handle on this when the X bolt gets back here and the other 12fv shows up.
 

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Note that copper fouling build-up can cause a constriction you feel slugging the bore, too. If you don't have a borescope to check for that, having had a Savage barrel that copper fouled badly and fast (in just ten rounds, accuracy was diminishing), I can tell you that putting in a chamber plug and flooding the breech end with KG-12 for half an hour may well be your best bet. Bore Tech Cu++ also works well, but expect to leave it for an hour or two. The advantage to Cu++ is it turns blue, so you know you got copper out, where KG-12 goes from tan to an orange-ish tan, so even though it eats more copper faster than any other copper cleaner I've ever tried, it gives you little indication of what it has done.

Hey, so have I!
 
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