6.5 Credmoor vs 7mm-08

[toddc]

Please explain. I do have a 6.5X47 built by RBROS that drives a 130 Berger at 3000 fps. Before I built this gun I researched the Creed and the 260 and the velocity was so close to the same I went with the X47. A 260 AI I agree can have more velocity. I see no love on here for the X47. Sorry that I am not a 260 or a Creedmore fan boy.

Exactly because of what I have been saying. Wildrose's point which is 100% correct is that the two cartridges loaded to the same pressures yields the 260 outrunning the 47. It's math.
The real world reality is that the 47 can run REALLY close to the 260 because of brass design, thickness and primer/flash hole, without SHOWING pressure. The pressure is there, we just don't see it.
Lots of guys run the 47 almost as fast as a 260 because they CAN. They are over pressure but there are no SIGNS of it.
Build a 260 with brass with the same thickness, hardness and a small primer hole and pocket and you can compare apples to apples. That isn't the real world most live in however.
Guys running the 47 in the same area as the 260 are doing it by relying on the brass to hold over SAAMI pressure and are getting away with what would cause issues in a 260 or Creed.
This kind of stuff is more common than many realize. There is Wildrose's version of internal ballistics which is THEROTECIALLY and ABSOLUTELY CORRECT and your version of real world ballistics which is REALISTICALLY CORRECT.
You can run your 47 nearly as fast as a 260, however you are doing it at a higher pressure than the 260 and the brass is masking your pressure signs. Happens every day. Doesn't make it smart and there is always the chance that ONE particular piece of brass or primer out of 1000 won't handle it and you will have primer in your eyes.
I have seen this stuff many, many times. Not only does brass MASK pressure signs, but actions, primers, barrels and powders do also.
Lots of guys are running over SAAMI to achieve the velocity that they do. Some combinations ALLOW this and others won't. A stock non trued action will USUALLY show pressure before a custom. Some chambers because of finish will SHOW less pressure than others. Tons of variables that allow people to REALISTICALLY achieve that which is THEORETICALLY impossible by CHEATING the pressure gods.
Wildrose is RIGHT. The 260 loaded the same way as the 47 will outrun it. Just a lot of guys run the 47 hotter than the 260 and get away with it for the most part due to a lot of different factors.
Run both loads thru Quickload and actually MEASURE pressure not pressure SIGNS and the 260 is faster.
Load both to show pressure SIGNS and who knows which will cry uncle first.
Unfortunately the real world we load to SIGNS not PRESSURE. If we had commonly available pressure testing systems that EVERYONE used there would be a lot less talk of the 47 running in the same league as the 260. Until we do, guys will hotrod stuff and SOME will pay for it sooner or later.

 

[BEEMAN]

Thanks for the reply, it makes total sense. I do agree that custom actions, reamers and barrels all make a difference. Maybe this is why I get such good performance out of my X47. RBROS has done a lot of testing in developing their reamer and loads and it shows.

 

[toddc]

I don't know what pressure my 6.5X47 is running. When Travis built my gun I asked if his load that he developed for me was at MAX. He assured me it was not. So if he says that I am not at max and am driving a 130 Berger at 3000 fps out of a 26" barrel do you guys think I am running to much pressure? The gun,brass and primers so zero signs of pressure.

You are dealing with exactly what I have been talking about. Your setup will MASK pressure incredibly well. If you are running MUCH over published data you are PROBABLY over. You will most likely be fine but anytime you are running faster than you should be, there is a risk. The only way a 47 will run with a 260 is by being over SAAMI. You can realistically get away with it but as Wildrose has pointed out there are no free lunches. Loading to pressure signs and backing down a bit has been done forever. It works but results in a lot of guys running over THEORETICAL max.

 

[Hondo64d]

I don't know what pressure my 6.5X47 is running. When Travis built my gun I asked if his load that he developed for me was at MAX. He assured me it was not. So if he says that I am not at max and am driving a 130 Berger at 3000 fps out of a 26" barrel do you guys think I am running to much pressure? The gun,brass and primers so zero signs of pressure.

It is most certainly over the specs that Lapua set for the case, 63,000 PSI. But the reality is the x47 case will handle a bunch more than that, especially when coupled with an action that has a small firing pin and hole and a small ejector plunger and hole, both of which help prevent brass flow. I don't want to find out where the pressure limit is for the x47 brass is, so I won't load any hotter than what a CM or .260 will do velocity wise. My last custom .260's favored load would push a 130gr VLD at about 2940 from a 24" Brux barrel. If I pushed it any more, I would start getting ejector swipes on the case head. That usually happens at about 70,000 PSI or a little more. That tells me that if I am pushing a 130gr VLD at more than 2940 from a 6.5x47 with its smaller capacity, I am certainly exceeding 70,000 PSI.

Do I load my 6.5x47 to more than the 63,000 PSI spec? Certainly. But there are limits. If I start seeing brass flow or primer pockets start to loosen after a few loads, it's time to back off, as those are visible signs the brass is starting to be stressed. My favored loads from my Criterion 26" barrel push a 130gr VLD at about 2850 and a 140gr Amax or ELD at about 2790.

John

 

[toddc]

It is most certainly over the specs that Lapua set for the case, 63,000 PSI. But the reality is the x47 case will handle a bunch more than that, especially when coupled with an action that has a small firing pin and hole and a small ejector plunger and hole, both of which help prevent brass flow. I don't want to find out where the pressure limit is for the x47 brass is, so I won't load any hotter than what a CM or .260 will do velocity wise. My last custom .260's favored load would push a 130gr VLD at about 2940 from a 24" Brux barrel. If I pushed it any more, I would start getting ejector swipes on the case head. That usually happens at about 70,000 PSI or a little more. That tells me that if I am pushing a 130gr VLD at more than 2940 from a 6.5x47 with its smaller capacity, I am certainly exceeding 70,000 PSI.

Do I load my 6.5x47 to more than the 63,000 PSI spec? Certainly. But there are limits. If I start seeing brass flow or primer pockets start to loosen after a few loads, it's time to back off, as those are visible signs the brass is starting to be stressed. My favored loads from my Criterion 26" barrel push a 130gr VLD at about 2850 and a 140gr Amax or ELD at about 2790.

John

Great post.
I stopped running ejectors springs on my Savages a while back for accuracy reasons.
Then I got smart and seated a pin flush with the bolt face.
The Edge I was running that setup on went from 2850 with a 300 SMK to 3100 with a heavier load WITHOUT showing pressure signs. HMMMMMM.
Then I tried to reload the 3100 FPS brass. Uhhhhh darn it the primers keep falling out after 1 loading. Primers were fine......Nosler brass wasn't.
Pressure signs and PSI are two totally different critters.

 

[MudRunner2005]

Please explain. I do have a 6.5X47 built by RBROS that drives a 130 Berger at 3000 fps. Before I built this gun I researched the Creed and the 260 and the velocity was so close to the same I went with the X47. A 260 AI I agree can have more velocity. I see no love on here for the X47. Sorry that I am not a 260 or a Creedmore fan boy.

I agree with you on a lot of things, but I must disagree on the 6.5x47L being that hot of a round at normal pressures. Even Travis @ RBros says that during their tests, the 26" 6.5x47L was only shooting 2,825 MV average, the 26" Creed and 26" .260 Rem were both at 2875, and their 26" .260 AI was right at 3,000...When all were compared with the same exact bullets.

Post #3, Travis' own words...

http://www.longrangeonly.com/forum/showthread.php?1878-Which-6-5-so-many-choices

 

[BEEMAN]

Yeah not sure what has changed. I asked Travis about which one he would go with and he recommended the 6.5X47. Personally I could not be happier. He did tell me that depending on barrels speed could differ up to about 40 fps. Said when I got mine it should be around 2925-2950 fps and settle in very close to 3000 fps after 100-200 rounds and that is exactly what my gun did. I guess when I said it will do what the 260 and Creed will do I meant that they are so close it makes very little difference. What's another click or two on the scope. That is a good link you posted and they are only 75 fps apart which to me is nothing. I still can't believe the speed I get with my X47 every time I look at that little case. To me it is very impressive. I run 42.2 gr of H4350. My 6.5 Sherman takes 63-64 gr of N570 to make 3339 fps with a 140 Berger with a 28" barrel. 22 more grains of powder to push a 10 gr heavier bullet 300 fps. Sounds in line to me. I do think if Lapua comes out with brass and a small primer it will really step up the Creedmore. I do agree lots of us do run over pressure without knowing it. I am sure my Sherman is over pressure but is right in line with what velocities other guys are getting. It is not far off a 26 Nosler or the 264 WM. Maybe it shouldn't be either???

 

[toddc]

Yeah not sure what has changed. I asked Travis about which one he would go with and he recommended the 6.5X47. Personally I could not be happier. He did tell me that depending on barrels speed could differ up to about 40 fps. Said when I got mine it should be around 2925-2950 fps and settle in very close to 3000 fps after 100-200 rounds and that is exactly what my gun did. I guess when I said it will do what the 260 and Creed will do I meant that they are so close it makes very little difference. What's another click or two on the scope. That is a good link you posted and they are only 75 fps apart which to me is nothing. I still can't believe the speed I get with my X47 every time I look at that little case. To me it is very impressive. I run 42.2 gr of H4350. My 6.5 Sherman takes 63-64 gr of N570 to make 3339 fps with a 140 Berger with a 28" barrel. 22 more grains of powder to push a 10 gr heavier bullet 300 fps. Sounds in line to me. I do think if Lapua comes out with brass and a small primer it will really step up the Creedmore. I do agree lots of us do run over pressure without knowing it. I am sure my Sherman is over pressure but is right in line with what velocities other guys are getting. It is not far off a 26 Nosler or the 264 WM. Maybe it shouldn't be either???

That's the whole dilemma with PSI versus PRESSURE SIGNS. PSI is PRESSURE but PRESSURE SIGNS aren't PSI.
Most people aren't aware that pressure goes down as the SHOOTER gets older.
As my eyes aged I found I had to go to a good magnifying glass to stay on top of things.
I see guys posting pics of brass that terrify me and they think it looks fine.
Until a cheap reliable way to measure REAL PSI comes about we have to rely on suspect factory and fellow reloading guys data, all of which is developed in guns other than our own. In order to be safe, we may not get all our rifle will give and we may not be safe even then.
I have been looking at strain gauges but reliability and calibration still seems to be an issue.

 

[MudRunner2005]

Yeah not sure what has changed. I asked Travis about which one he would go with and he recommended the 6.5X47. Personally I could not be happier. He did tell me that depending on barrels speed could differ up to about 40 fps. Said when I got mine it should be around 2925-2950 fps and settle in very close to 3000 fps after 100-200 rounds and that is exactly what my gun did. I guess when I said it will do what the 260 and Creed will do I meant that they are so close it makes very little difference. What's another click or two on the scope. That is a good link you posted and they are only 75 fps apart which to me is nothing. I still can't believe the speed I get with my X47 every time I look at that little case. To me it is very impressive. I run 42.2 gr of H4350. My 6.5 Sherman takes 63-64 gr of N570 to make 3339 fps with a 140 Berger with a 28" barrel. 22 more grains of powder to push a 10 gr heavier bullet 300 fps. Sounds in line to me. I do think if Lapua comes out with brass and a small primer it will really step up the Creedmore. I do agree lots of us do run over pressure without knowing it. I am sure my Sherman is over pressure but is right in line with what velocities other guys are getting. It is not far off a 26 Nosler or the 264 WM. Maybe it shouldn't be either???

I know pretty much everything I have is running at higher pressures than recommended... That's how i'm getting such amazing velocities out of things that should not be...Like my .30-06 AI pushing almost .300WM velocities.

 

[Dgd6mm]

I do not run anything over pressure, your only inviting trouble when you do this. I will run some of them up towards max but not over. There is a maximum for a reason...and if for anything functionality is a must at all times. I like both these cartridges and they both shoot excellent near maximum pressure.

 

[adam32]

I'm just not sure why anyone would want to push the envelope that hard...if you want to push a bullet faster then step up to a bigger case...

 

[MudRunner2005]

I do not run anything over pressure, your only inviting trouble when you do this. I will run some of them up towards mags but not over. There is a maximum for a reason...and if for anything functionality is a must at all times. I like both these cartridges and they both shoot excellent near maximum pressure.

I'm just not sure why anyone would want to push the envelope that hard...if you want to push a bullet faster then step up to a bigger case...

The difference in me and most people, is that I know I'm flirting with disaster...And I understand the dangers and fully accept the responsibility if I blow up my own rifle. I also inspect EVERY case I shoot for pressure signs or excess wear signs immediately after firing it. That way I know if I'm getting to a dangerous level to stop shooting and move on to the next rifle. The last thing I ever want to do is endanger anyone around me, so when I go the range, I usually try to leave a booth or 2 between me and the next guy. But sometimes they're crowded and it just doesn't happen that way. That's why I'm looking to buy my own land and build my own personal range.

 

[toddc]

I do not run anything over pressure, your only inviting trouble when you do this. I will run some of them up towards max but not over. There is a maximum for a reason...and if for anything functionality is a must at all times. I like both these cartridges and they both shoot excellent near maximum pressure.

How do you know that? Because you run under a MAX book load? Really doesn't mean anything other than you are under max BOOK load. This whole thread devolved into a discussion of visible pressure signs, none of which will accurately show the PSI you are at. My AR Creed will run 2 gr over max of Superperformance and yet 1gr under max of RL17 scares me to death. Without an accurate pressure system we are all running in the dark to some extent. Book max is a guideline as always and nothing more.

 

[toddc]

I'm just not sure why anyone would want to push the envelope that hard...if you want to push a bullet faster then step up to a bigger case...

Because they are wringing out that PARTICULAR barrel, action, brass, primer and powder combo. Just like the manuals say "These are recommended loads not necessarily safe in YOUR rifle". Why should someone running Lapua brass, custom action, fast barrel and HBN have to run the same loads as a guy shooting RP on an action with only one lug touching at 25% contact, a patchy barrel and a lot of oversize bullets?
There are too many variables present for a book max to be safe OR be anywhere near any particular rifles max.
I guess that's why we work up loads.