6.5 SLR vs 6.5 Creedmoor

[Macht]

I'm getting ready to rebarrel my hunting rifle, a Sako 75 short action, and already have a 6.5mm blank on hand. The only real decision I have left is what cartridge to chamber in. I hunt suppressed, so I'll be going with a 22" finished length. While it's primarily a hunting rifle, it will also see a bit of range time on steel in the 250-1150 range. I intend to load only two bullets, the Barnes 127 LRX and the Nosler 140 RDF. With those things in mind, what would be my best cartridge choice of the two listed? I've compiled the following lists of pros and cons.

6.5 SLR
Pros:
- Longer neck (slightly longer barrel life)
- Have roughly 200 pieces of R-P 260 brass on hand
- More powder capacity

Cons:
- No Lapua brass without neck turning
- Wildcat

6.5 Creedmoor
Pros:
- Lapua brass (small primer, would only need CCI #450s for everything I load)
- Availability of factory ammo in a pinch

Cons:
- No brass on hand
- Slightly less powder capacity

Given those pros and cons, I feel like the real question is whether or not the new Lapua Creedmoor brass will allow the Creed to compensate for the slightly lower case capacity.

TLDR - Would 6.5 SLR or 6.5 Creedmoor be a better choice for launching the 127 LRX and 140 RDF out of a 22" barrel?

 

[sandwarrior]

Wow! Not so much a tough one when you think about it. Even if you didn't have the opportunity to buy Lapua brass (with small primer) the Hornady does pretty good..

So, the comparison as I've seen it:
6.5 Cr is a massaged .300 Sav. case (with shorter neck) to fit in a short action. The only drawback is feeding. With short action magazine, this isn't much of a problem. With a long action, (like the M24...which is completely gone now, I understand) The feeding on "offisize cartridges" is difficult.

The SLR's are a good idea, but they retain the length of the .243/.260. Which is mostly good, but leave very little variation in the length you can have with these in a short action. They are also "offsize" as the shoulders are blown out as well..

The bottom line is you are not really gaining any case capacity. What you gain with the SLR's is a longer neck which helps with throat erosion. But, limits stretching out the rounds when throat erosion occurs. Added: Meaning you don't have a lot of room to chase lands

 

[Milo 2.5]

Last August I built a 6.5slr, with more case capacity I thought it would out perform the creed I had in the past. Trust me, with Win, never tried Rem brass, now wish I had given Lapua 243 a go, the extra case capacity was not usable w/o pressure. I pulled the barrel at 600rds and shelved it waiting for 6.5 creed Lapua brass. Being I had formed cases, I rebarreled to 6slr which right now is getting a new barrel, the 6 seems to hold it's own.
So my vote was for the creed, small pocket brass, w/o much capacity loss for the win.

 

[Macht]

Thanks for the feedback so far! I don't know how much it changes anything, but I mentioned that the rifle is a Sako 75 because the mags for that rifle allow seating to roughly 2.95", which gives the SLR a little more room to play with than most mags.

 

[xdeano]

I looked at both the 6slr and 6.5slr many years ago and decided the benefits weren't as much between the 260 over the 6.5slr as they were between the 243 and 6slr. You gain a bunch in the 6slr, not so much with the 6.5slr. If it were me doing a 6.5 Cal for a short action, it would be a 6.5x47L right now. Excellent brass, decent life, and it's efficient. Less powder burned for the same velocities.
just my 2 cents.

xdeano

I ended up doing a 6slr. Love the round.

 

[PinkVapor]

I'd like to re-barrel m M75, do you suggest a gunsmith?
Thanks!

 

[Rockfish Dave]

Running a 6.5 SLR-S improved and getting 2925fps with single digit ES. I wrote a thread on the accurate shooter forum.

http://forum.accurateshooter.com/threads/6-5-slr-s-improved-ready-for-testing.3821760/

I have zero pressure and great accuracy.

I can share the reamer print if you are interested. I will likely never change cartilages given the performance is bumping into 6.5-284WIN velocities without any issues. I have no idea of what the final max velocity is since it shows no signs of pressure and has additional capacity to spare.

Nothing wrong with the CM but if you load your own there is no reason not to go all in.

 

[Supersubes]

Running a 6.5 SLR-S improved and getting 2925fps with single digit ES. I wrote a thread on the accurate shooter forum.

http://forum.accurateshooter.com/threads/6-5-slr-s-improved-ready-for-testing.3821760/

I have zero pressure and great accuracy.

I can share the reamer print if you are interested. I will likely never change cartilages given the performance is bumping into 6.5-284WIN velocities without any issues. I have no idea of what the final max velocity is since it shows no signs of pressure and has additional capacity to spare.

Nothing wrong with the CM but if you load your own there is no reason not to go all in.

Id be interested in the print. Pm sent

 

[Rockfish Dave]

Will send it this week. A pity the pictures don't show as they were pretty detailed regarding the fired brass. You could see that there was in fact no pressure.

 

[Edsel]

Will send it this week. A pity the pictures don't show as they were pretty detailed regarding the fired brass. You could see that there was in fact no pressure.

Me too, Dave!

I've been interested in this round for some time, but there have been many variations with reamer specs...

Always got me confused.

 

[Rockfish Dave]

Will do

 

[Rockfish Dave]

They are also "offsize" as the shoulders are blown out as well..

The bottom line is you are not really gaining any case capacity. What you gain with the SLR's is a longer neck which helps with throat erosion. But, limits stretching out the rounds when throat erosion occurs.

Not sure what you are trying to say. The shoulder changes from a 20 degree to a 30 degree shoulder. The way this is accomplished is by pushing the shoulder back to make the 30 degree shoulder this elongates the neck. There is no change to the case body. Nothing is "blown out".

The longer neck has no impact on chasing the lands either so not sure what you are trying to say there either. What the longer neck does do is allow for a broad selection of projectiles that can be used.

SMH..

 

[Rockfish Dave]

My improvement does blow out the taper but it is not the standard SLR or SLR-S chamber(s).

 

[Rockfish Dave]

Me too, Dave!

I've been interested in this round for some time, but there have been many variations with reamer specs...

Always got me confused.

PM me your email address and I will send to you.

 

[sandwarrior]

Not sure what you are trying to say. The shoulder changes from a 20 degree to a 30 degree shoulder. The way this is accomplished is by pushing the shoulder back to make the 30 degree shoulder this elongates the neck. There is no change to the case body. Nothing is "blown out".

The longer neck has no impact on chasing the lands either so not sure what you are trying to say there either. What the longer neck does do is allow for a broad selection of projectiles that can be used.

SMH..

The shoulder is the same width on a 6.5 Creed as a .260. Except the distance from the rim to the shoulder is shorter, making the case wider. I tried my 6.5 Creed cases in a short DBM (.308) and they worked. They do not work in my long action made for a 30-06.

Since it was February since I posted this, I believe I was referring to the SLR in which the shoulders were blown out as well (added) "on the SLR improved cartridges I've seen.". The rim of the shoulder remains the same distance from the rim of the case. Except it goes from .454" to .459". That taper difference makes them a bit harder to feed. The angle of the shoulder is pushed back to get the 30 deg. as you said.

added: A longer neck will help some with throat erosion. Depending on how the cartridge is loaded. The 30 deg. shoulder is what helps limit case stretch.

 

[Rockfish Dave]

I'd have to check my diminsions but I went very aggressive on reducing the taper and have had ZERO issues feeding from aics magazines. My understanding is it is 40 degree or greater that issues feeding. Taper has nothing to do with it. The issue with minimal taper is extraction.

What are are you basing the feeding issues on, because it definitely does not reflect my personal experience.

To date I am the first and one of three that are running improved versions of the cartridge. In fact I just received a PM minutes ago from a fellow who used my design and is getting an average velocity of 3,035 fps with 140gr ELD's. Unfortunately he didn't give me his load information only a pic of his magnitospeed screen.

 

[Rockfish Dave]

Clearly I am leaving a lot of velocity on the table at 44grs of H4350, but there is no argument with the low ES and accuracy. Btw: this the first and only time I have been able to get single digit ES from a cartridge.

 

[Rockfish Dave]

Pulled my reamer print, standard SLR-S reamer print and the velocities from a new adopter previously mentioned as attached images.

 

[sandwarrior]

I'd have to check my diminsions but I went very aggressive on reducing the taper and have had ZERO issues feeding from aics magazines. My understanding is it is 40 degree or greater that issues feeding. Taper has nothing to do with it. The issue with minimal taper is extraction.

What are are you basing the feeding issues on, because it definitely does not reflect my personal experience.

To date I am the first and one of three that are running improved versions of the cartridge. In fact I just received a PM minutes ago from a fellow who used my design and is getting an average velocity of 3,035 fps with 140gr ELD's. Unfortunately he didn't give me his load information only a pic of his magnitospeed screen.

Feeding issues for the 6.5 Creed are in a Win 70 long action. They feed fine out of a Savage short action centerfeed.

 

[Rockfish Dave]

Feeding issues for the 6.5 Creed are in a Win 70 long action. They feed fine out of a Savage short action centerfeed.

Well that is the issue, not the shoulder or taper...

SMH again....

 

[sandwarrior]

Well that is the issue, not the shoulder or taper...

SMH again....

The geometric shapes, i.e. taper, is allowing the rear of the case to fall downward. That combination will feed a .260 or .308. Because the have slightly more case taper and align with the follower.

The reason the Savage centerfeed will feed them is the shorter follower is not pushed out of balance, like the long follower. And, the feed lips grasp both sides of the case, not just one. Much as in the case of your AI.

 

[Rockfish Dave]

The geometric shapes, i.e. taper, is allowing the rear of the case to fall downward. That combination will feed a .260 or .308. Because the have slightly more case taper and align with the follower.

The reason the Savage centerfeed will feed them is the shorter follower is not pushed out of balance, like the long follower. And, the feed lips grasp both sides of the case, not just one. Much as in the case of your AI.

The standard SLR and SLR-S (for short action magazine fed) has no change in the taper from the parent 243 or 7-06 or 308WIN parent case. The case OAL is relatively unchanged, and no change in the body length from rim to shoulder. Which tells me that even if you are correct, it would not have issues feeding in your long action from what you have said.

I wish people would refrain from commenting on things they clearly do not have expirience with or have failed to adequatly research, it would cut down on the amount of incorrect info that is floating around.

This (or at least my) design is a step forward in efficiecy, and mis-information will deter others who otherwise would appreciate the leap forward in performance from even trying it...

Brass is cheap and good quality
It is very forgiving of load variance (accuracy while in load development)
No big deal to form from 243WIN brass
And given the lack of pressure the brass should last along time if annealed

The fellow followed up with me and said he got ejector swipes at 47.3grs using plama brass.

Still SMH..

 

[Rockfish Dave]

The shoulder is the same width on a 6.5 Creed as a .260. Except the distance from the rim to the shoulder is shorter, making the case wider. .

Just caught this, more bad info. The Creedmore (and 6.5x47) have significantly less taper per inch than the .308Win family of cases. If anyone cares I can check my notes and post up the actual numbers.

I have to admit this is really getting on my nerves.

 

[sandwarrior]

The standard SLR and SLR-S (for short action magazine fed) has no change to the taper. The case OAL is relatively unchanged, as is the length from rim to shoulder. Which tells me that even if you are correct, it would not have issues feeding in your long action from what you have said. Then why does your print show .4634 at the shoulder rim...that is a change in case taper and it WILL affect feeding. How much may depend on what kind of magazine you are using.

I wish people would refrain from commenting on things they clearly do not have expirience with or have adequatly researched, it would cut down on the amount of incorrect info that is floating around.
I wish would be inventors like yourself would take marketing 101 somewhere and at least learn to listen to their customers. I get what you are pushing is proprietary and you want 5 times the going price for dies, but there is a problem. Please pay attention and fix it. Or, at least address why it will or will not work. I have researched it and I have worked with this cartridge. It's an improvement over the .243. But, if I want a better 6mm improvement, I'll just use the RCBS 6mm improved. I wanted over-bore once so I got a 6-.284.

You're probably the only guy that's ever done this and the rest of us are just dumbasses.

This (or at least my) design is a step forward in efficiecy, and mis-information will deter others who otherwise would appreciate the leap forward in performance from even trying it... As stated above, it's a leap forward in efficiency. But powders and especially bullet design have made bigger strides by far than case shapers.

Brass is cheap and good quality What Brass? Good brass is Lapua. That is expensive and not always available. And, only available from certain dealers. Their Palma brass only comes in .308. To neck that down requires turning necks.
It is very forgiving of load variance (accuracy while in load development) The .243 is a more forgiving cartridge. The original 6mm less forgiving. Big tapered cases don't like hot loads
No big deal to form from 243WIN brass. Neither is the .243 AI, 6.5mm AI, 6mm RCBS Imp., 6mm-250 Imp,, or 6-300 Sav imp. (and 6.5) Even the 6.5 International.
And given the lack of pressure the brass should last along time if annealed Lack of pressure? Got some Piezo data on that? There is no free lunch. The speeds you are attaining from the volume of your case says "High Pressure". Even in a long barrel with slow powder. You claim a 300 fps advantage over factory 6.5 Creed. It is certainly doable. Again, no free lunch though, your pressure curve goes up really fast with an improved shoulder. And with high pressures comes short barrel life. Some are willing to just consider barrels a cost factor. Others like me like 'em to last a little while.

The fellow followed up with me and said he got ejector swipes at 47.3grs using plama brass.

Still SMH..

 

[Rockfish Dave]

Again more bad information.

I am not, and do not sell anything. In my original thread posted on the accurate shooter forum I recommended, based on personal experience, that adopters go through Whidden Gun works based on speed of delivery and quality of dies.

Regarding your comment on you being a dumb ass, your words, but I will not argue with you on that point.

Regarding brass: There is a paper on the metalurgical properties of the various brass manufacturers. The win and lapua are very similar in properties but Win is thinner. All that is moot if it doesn't shoot. Mine absolutely does.

Regarding pressure: No I do not have access to the equipment mentioned but since you lead one to believe you do by the boldness of your comment feel free to loan me it and I can validate my observations to your satisfaction. You can also look at the photos on the accurate shooter forum post and see the fired cases for yourself and verify that there are no tell tale signs of pressure. I am hesitant to mention that I had designed this case based upon a white paper I had read on internal ballistics. The reason is: I didn't save it, and no longer have access to it. A properly designed case wil allow for ignition with out the pressure spike in the case like some more conventional designs. Pressure curve is smoother allowing it to expend the energy actually moving the projectile forward rather than deforming the brass.

In closing I think the only accurate comment you made was regarding being a dumbass.
I can't argue with that.

 

[sandwarrior]

Here's my frustration. You have a great cartridge capable of doing what you say. Fact. I agree with you on that.
There are two issues I don't agree on and those have come from testing in a laboratory with Piezo equipment. Pressures. The case may produce less pressures than some of it's contemporary wildcats. But, to produce the velocities you get from the case you use with the bullet you are using means you are getting high pressures. High pressures lead to premature barrel erosion. In the case of the SLR that is slightly mitigated by the longer neck.

The other problem is that geometric changes to case shape can cause feeding issues. Especially in a staggered configured magazine where one side of the case is held by a lip, and the other side is open. In order for that system to work the one lip and follower must match the geometric shapes of the cases while stacked in the magazine.

In your case, and to some extent mine, that problem is solved by either a single stack or centerfeed magazine. Where the case is held by opposing magazine lips. Which are flexible enough to conform to the individual case shapes.

 

[Rockfish Dave]

Again my version is not the standard version. Standard version still gets >2,900 fps. Mine with the modifications does so with greater case capacity and lower pressure.

Standard SLR and SLR-S will feed out of any double stack magazine that reliably feeds 308 WIN based cartridges.

You are basing your comments on my version. I am going to go out on a limb and say it should still feed from a double stack with some feed lip tuning since WSM and RSAUM have done so. Though I do not have personal experience with them, but the 6.5 4s can and I trust George at GA Precision.

Your comments remind me of comments made by David Trout of Thouroghbred Rifes and now Stller actions. He was telling me the 284 Shehane wouldn't feed from a magazine. Well I was undeterred and built one and it feeds like butter.

You continue to to make baseless comments and some newer shooters will take what you say as fact. Please try to be more responsible if for no other reason than to promote shooting.

My comments are based on firsthand experience and applying what I have learned through research. You on the other hand are just repeating platitudes.

 

[sandwarrior]

Well, good luck with this project.

 

[Ogy48]

Running a 6.5 SLR-S improved and getting 2925fps with single digit ES. I wrote a thread on the accurate shooter forum.

http://forum.accurateshooter.com/threads/6-5-slr-s-improved-ready-for-testing.3821760/

I have zero pressure and great accuracy.

I can share the reamer print if you are interested. I will likely never change cartilages given the performance is bumping into 6.5-284WIN velocities without any issues. I have no idea of what the final max velocity is since it shows no signs of pressure and has additional capacity to spare.

Nothing wrong with the CM but if you load your own there is no reason not to go all in.

I would be interested in the print. I'm working on pet project custom AR10 that I have spent more $$ on than my kids. LOL. I want it to be a different than the rest rifle. There are tons of CM rifles at the range, and I want to have something different

 

[Steel head]

I would be interested in the print. I'm working on pet project custom AR10 that I have spent more $$ on than my kids. LOL. I want it to be a different than the rest rifle. There are tons of CM rifles at the range, and I want to have something different

Creedmoor is gonna fit AR-10 mag limitations better than 6.5slr.

Want different

Run a 25 Creedmoor it 6.5x47.