I can't believe I got a Creedmore
- Thread starter Ruger007
- Start date
Don't switch from 308 or it will feel like cheating
Calibers that render another obsolete in every performance metric are best avoided as the devil's gift.
ScottMisfits
CGN Regular
Like it's said before, the 6.5 Creedmoor is nothing special, but it works. May people feel that bigger is always better. The Scandinavian countries have been using the 6.5 and 7mm cartridges for over a hundred years with a great deal of success. The 6.5 CM is just a take off of that. It's just the latest rendition of it. If you already have something similar, cartridge or calibre wise, that does what it will do, great. If you're someone who likes to try something different from what you're used to, give it a shot. It's like anything else out there, it fit's the bill for someone. Life would be boring if we all shot the same varmint cartridge, the same big game cartridge, or the same target cartridge. I have, or have had 243, 6.5CM, 7RM, 308, and 30-06. As long as they shoot how I want them to shoot, I'm happy taking any of them out with me for what I want. Not as much experience as some, without question, but what I have works for me and that's all that should really matter.
The 6.5 Creedmore is a little special actually, especially if you compare it to a SAMMI spec 308. It's really all in the seating depth of the bullet and the freebore in the chamber that is typically used for each of the two.
A 308 typically has a short freebore and bullets are typically seated short. Therefore we rely upon the sloppy case and sloppy neck to align the bullet to the bore, and it does not do a very good job.
A 6.5 Creedmore is offered with heavy bullets seated way out of the neck, by virtue of a shorter case. This allows the freebore to help align the bullet to the bore. This makes the round very tolerant of runout.
Now, you can design your own custom chambering reamer so you can shoot long heavy high BC bullets out of a 308 and seat them real long, like most F Class shooters do. You then quickly learn that a short action Rem 700 cannot eject that 185 grain Berger Jug, and the gun should have been built on a long action.
So to get the 6.5 Creedmore ish throat you need to run real heavy rounds in a 308. Now that means recoil increases.
Is the 6.5 Creedmore the holy grail of cartridges, who is to say... But it is a solid round if it meets your energy requirements.
As for flat shooting at long range, its a tight race between a variety of rounds. Crunch the numbers on a humble .224 Hornady 88 ELD or 90 grain A Tip at 2900 + FPS and you'll see the ballistics can be closely replicated with far less recoil if simply hitting a target is the objective.
The advantage of just about any cartridge lies in how well the feebore is used to align the bullet to the bore. Beyond that, its about the powder weight to bullet weight ratio. Most of the largely popular long range competition rounds run a powder charge that is right around 1/3 of the bullet weight, give or take a bit.
Considering this post, it's really about how any cartridge is specifically chambered that makes or breaks the deal and to debate the over the counter versions is a bit unfair when we can use a particular cartridge differently than typically offered by factories in mass.
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ScottMisfits
CGN Regular
I get what you're saying, to a point. these are the two most frequently compared to each other but you're comparing a granny smith to a macintosh apple. There are many crossovers but they are different. Special isn't the word for it. Different is.
Maybe semantics, maybe not. But let's be honest, it's just different.
When these 6.5CM vs .308 topics come up for discussion , I think it's important to remember a couple of things . Do the 6.5's have a ballistic advantage in the wind ? Yes . This does make them more forgiving . However , it comes at a cost , which typically , is significantly reduced barrel life . Also , Just because you have a 6.5 , doesn't automatically make you superior to the .308 guys ( or anyone else for that matter ) . Time after time , I see new 6.5 shooters get their butt handed to them on the range simply because they don't have the time invested in reading the wind . Even though it's the latest and greatest 6.5 , there still is wind deflection that has to be dealt with . An experienced .308 guy is still a formidable force to be reckoned with out to say 800M or so . Keep in mind that a good .308 can and will shoot better then the vast majority of shooters are capable of shooting them . That's reality . Training and time go a long way towards maximizing the potential of any cartridge . A .308 that will hold 1/2 MOA at distance is still a pretty awesome piece of kit .
I burned up 3 6.5CM barrels this passed summer, in a covid truncated season. Barrels are like tires. Burn 'em up and change 'em out.
Next.
Well, I wouldn't call it theory. Just think about the bearing surface on a bullet. Heavy bullets have a long bearing surface... That's the part of the bullet that is cylindrical between the boat tail and the nose.
When a bullet is long and heavy and seated into the case only so fare that the corner between the boat tail and the bearing surface is forward of the neck to shoulder donut area, the case capacity is maximized, the maximum amount of the bearing surface is protruding from the case and is available for the parallel freebore to align the bullet to the rifling.
This is one of the reasons competition guys design their own custom reamers.
I have for example, 3 chambering reamers of my own design. One is for 308 for 155 grain Palma bullet, one for the 185 Berger Jug and one for 223 for the 88 grain Hornady ELD M and 90 Grain A Tip. All of these reamers have freebores that keep the base of the bullet forward of the donut. The freebore diameter is also as close to the bullet diameter as I consider safe. I designed another reamer for the 6x47 Lapua but sold that along with the rifle and dies some years ago.
If the freebore diameter is too tight, a fat bullet could get stuffed back into the case and that would create high pressure, so we need to make sure that doesn't happen, but the closer to a slip fit that is, the better it will align the bullet to the bore.
I see guys crediting certain per cartridges because the traditional configuration is pretty much as I describe here, but we can do it with any cartridge if we want to. We just need to spend about $300 for the custom chambering reamer.
For competition purposes, I like to run tight turned necks that are also only clear about 0.001-0.002" This also ensures ideal bullet alignment to the bore and its admittedly overkill for most shooters needs, but for F Class, there's no such thing as overkill especially at long range.
Guys often lose sight of the benefit of a tight neck and turned necks. It minimizes brass rework during firing and resizing. It ensures best concentricity between the neck and body and therefore the bullet, and it provides the mechanism by which you can accurately determine neck hardness based on the amount of spring back after neck sizing. A tight neck also creates a pressure seal faster than a well cleared neck and that lowers your SD and ES.
The advantages go on if you start to think about what happens in that brief moment as the pressure builds and the bullet begins to move.
While its true that most shooters don't shoot well enough to shoot the difference and lack the ability to exploit the difference, on the other hand, you can't learn from a rifle you can't trust.
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Maple, thanks for the detail in your reply. I am not a competition/long range shooter but do shoot more than average and have some pretty decent actions and barrels...so always eager to take advantage of any design that will mitigate my performance at the bench. I too have several custom spec’d reamers that cut tight necks and my choice of freebore designed to seat (some) bullets with the neck/boat tail junction forward of the donut. I have a cross-sectioned chamber cut with one of my reamers to see how the loaded cartridge “fits” / sits. It would be interesting to do a similar cross-section with a SAAMI cut chamber for comparison.
I could be wrong, but I think by the time the bolt is closed, the cartridge is pretty much held in a position where neither the case neck or the bullet are laying against the bottom of the chamber?
I could be wrong, but I think by the time the bolt is closed, the cartridge is pretty much held in a position where neither the case neck or the bullet are laying against the bottom of the chamber?
Well, the extractor does certainly apply side pressure on the round. Some precision shooters will cut the ejector spring to reduce that preload for better accuracy. This is popular in bench rest and F Class for single shot rifles. If you do that on a repeater, you may have to manually remove fired cases since they wont actually eject.
But... Even with a full strength ejector spring, it can only drive the round as far as the clearances will permit. So we are now back to the clearance in the neck and freebore, but the amount of headspace and side wall resizing is also a contributing factor.
Bottom line is the closer everything fits and aligns the better, so far as you don't create binding on bullet release or bolt close or bolt open in the process.
This is where the "Always FL resize" advice is a step backward for "precision" shooters. The most dedicated shooters will pair the custom sizing die to the custom chambering reamer to minimize the amount of side wall resizing. You'll even see that on YouTube stated clearly by Speedy in an interview Eric Cortina about 30 minutes into the video.
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The extractor should have absolutely no influence on a chambered round. If yours does, I would get it fixed.
How can you make such a broad claim with no explanation as to how you came to such a conclusion?
The ejector spring applies several pounds of force. Try and compress it with hand pressure and you will be putting your shoulder into it.
It drives the cartridge forward as far as it is capable of going, and applies said pressure from one side which creates a cartridge alignment bias to one side if the side wall is not a tight fit.
How can you suggest that much force has no effect on alignment?
Re-read what I wrote, and try again. Words are important.
My, “broad statement” stands. If your extractor is applying side load on your cartridge in the chamber, your gun is broken.
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