Range Report Trying to decide between 260 remington and 7mm-08 in a 20-21 inch platform

[matt2143]

I currently shoot a 20" .308 and would like to change things up a bit and have a barrel cut for my AX in either 260 or 7mm-08.

I know currently there is a hold on production of the 162 AMAX for the 7mm-08 but there are a few other performers out there.

Here is what I want to accomplish; better wind performance over my .308, must be a shorter barrel (21" max), I have 2500 LC LR cases I have once fired and would find the resize to 7mm-08 would lessen the prep steps by one, Occasional varmint hunting at distance, long range UKD matches to 1250 yards, with the AX I am stuck with a .308 parent case so no SAUMs.

I currently run 178 BTHP with a BC of .530 at 2750 and I shoot in DA's from -250 to 6500.

I have been reading for days on the topic and find bits of info here and there but most involves longer barrels. Also I have seen a few 7 Creedmores and they also interest me but I am unsure of any advantage the 7 Creed would have over a 7mm-08.

I also realize the 7mm would dictate nothing but hand loading for what I do and honestly not having access to manufactured ammo is not a concern at this time.

I am interested to hear thoughts from those that have done it.

 

[matt2143]

^^^^^^^^^^

 

[jbailey]

If you are doing a lot of UKD shooting out to 1250 yards, why are you cutting yourself short with such a short barrel? It is tough enough shooting at those ranges UKD with the big magnums and the 26"+ barrels, that a 20" barrel makes the task so much tougher. Anyway, the bullets that will really improve your wind drift profile, the 140's in 6.5 and the 160+'s in 7mm, are going to look like rainbow trajectories with a 20" barrel, from either cartridge. Honesty, if you are getting such good performance with your 308 (178gr w/ 0.530 G1 BC at 2750 is rocking it with a 20" 308), I would just keep it if you need that short a barrel...

 

[trebark]

If you are doing a lot of UKD shooting out to 1250 yards, why are you cutting yourself short with such a short barrel? It is tough enough shooting at those ranges UKD with the big magnums and the 26"+ barrels, that a 20" barrel makes the task so much tougher. Anyway, the bullets that will really improve your wind drift profile, the 140's in 6.5 and the 160+'s in 7mm, are going to look like rainbow trajectories with a 20" barrel, from either cartridge. Honesty, if you are getting such good performance with your 308 (178gr w/ 0.530 G1 BC at 2750 is rocking it with a 20" 308), I would just keep it if you need that short a barrel...

Heed the word of Mr. Bailey!

 

[matt2143]

What's up guys. I figure I should I am not that concerned about UKD attributes of my caliber. I do pretty well in that arena (not enough to want to run 208 amaxs at 2450 out my rifle!). I guess my only concerns at this point is wind and enough energy on target. with 175 smks moving 2750 I was able to see misses in the dirt out to 1300 whereas a 7 WSM moving a 162 amax out of a 30" barrel provided no evidence of missies at 1890. Just didn't have enough juice.

 

[BoilerUP]

260 will give you 2700fps or more with 140-class bullets and a 20" barrel.

178s @ 2750 from a 20" 308 sounds pretty darn hot...but I say try 168 Hybrids and if you touch 2800 the 308 will still lag the 260 shooting 140 Hybrids but not enough to justify the expense of a caliber swap.

 

[thespecialist]

260 will give you 2700fps or more with 140-class bullets and a 20" barrel.

178s @ 2750 from a 20" 308 sounds pretty darn hot...but I say try 168 Hybrids and if you touch 2800 the 308 will still lag the 260 shooting 140 Hybrids but not enough to justify the expense of a caliber swap.

Yep, I was able to push 140's up around 2750 without pressure signs in my 20" 260 with H4350, R17 would have probably gotten me even higher than that. 123 Amax's seem to be it's preferred fodder though, running right at 2900fps with H4350 and almost a full grain below pressure signs.

 

[jbailey]

Matt-
in that case, I would say 260 Rem.

I'm a big fan of both calibers, but think the advantage of the 7mm is in the bigger bullets (e.g. 175gr SMK, 180gr Berger). A 7-08 at 20" will not push a bigger bullet at a MV that you will find attractive and then in the medium bullets in 7mm, you really only have one choice - the Hornady 162gr. As the current situation at Hornady illustrates, its never a good idea to rely on just one bullet. And what if the 162gr doesn't shoot in your barrel?

On the other hand, with the 260, you will have multiple bullet choices in three weight classes, all of them attractive relative to your needs and the 308: 123gr (at least 3 manufacturers making good bullets there), 130gr (again three, albeit these are tough to get right now) and then 140gr (again at least three). As mentioned above, 2700fps with the 140's is likely from a 20" barrel.

That is my thinking.

 

[matt2143]

Yea you are right about the 162 AMAX, currently Hornady has them on the temporarily discontinued list. Also that is pretty much like putting all my eggs in one basket as some of the other 7mm bullets are promising but being able to push them fast enough from a 7mm-08 in a shorter barrel would not net me anything.

After spending some time comparing tables on JBM ballistics it really does come down to numbers. I realize I enjoy shooting with my suppressor and having a 20" barrel with a can I really have no desire to go longer and in that I am essentially handicapping myself in the speed department. If I compare just the .308 and .260 in 123 scenars @ 2900, 140 AMAX @2760, 178 bthp @2750 and 185 Berger Juggernaut @ 2700 I can see that I am talking about a .9 mil difference in drop at 1K and something in the area of 1-1.8" wind difference with a 1 MPH crosswind. I think because I can quick change barrels on my AIAX I will buy a .260 barrel but in the end I think for my short barrel requirement it is all on me as a shooter. Changing calibers will likely not gain me much in the wind department. Although UKD stuff I would gain a slight edge with a faster moving .260 but I am less concerned with that part, that may change in the future.

Thanks for all the input guys and Bailey and Trebark I will see you guys at the next Match!

 

[BoilerUP]

What kind of load is gonna get 185s to 2700fps in a 20" 308?

I dunno much about 308 but that seems like an exceptionally fast barrel, a very hot load, or both.

If ya want apples to apples, run numbers for 6.5 140 Hybrid...but the 30cal 168 Hybrid is gonna be your best bet for 308 ballistics IMO.

 

[thespecialist]

2000MR might get the 185's there, loaded long and over a HEAVY charge, but I wouldn't want to be the one pulling the trigger.

 

[matt2143]

Yea I am running 178 BTHP's at 2750 over 47 grains of PP2000MR in LC brass with Fed 210 primers. Bumping the shoulders back .004" with an overall to ogive of 2.220" and COAL somewhere around 2.9xx". Since I am using AW length mags I can load out to 2.974".

I will be loading up some 178 AMAX and 178 BTHP over Varget this weekend for testing with CCI 200 and Fed 210 primers. We will see what this gun really likes.

 

[bh-ltr]

Boy thats some hot shit to get 178's at 2750 on a 20" tube. I've been loading 175SMK's with 44.3g of Varget over a Remington 9.5 primer to get 2577 fps. I'm using this load to match up with my previous load of 44.5g of Varget over a Federal 210 primer which produced 2580 fps. This is in a 20" 1in12 factory barrel. I like my 20" barrel but I'd like it a lot better if it was sending my 175's at 2750! That's just over 10" of wind difference at 1K for a 10mph wind.

 

[mdesign]

Matt....I'm a 7mm fan myself and have a 7-08 with a 22" barrel that yields 2725 fps with 162amax & 2000MR or 8208xbr. I've got a decent supply of 162's and I figure Hornady will come back once they get done putting their bullets into ammo or making other high volume bullets. I like to run suppressed as well and so 22" is a long as I go.

I got 243 with a barrel that is getting pretty tired...kind of thinking about what I was going to rebarrel with....a 260 or 7-08. JBM suggests they are close enough that I matter more than the cartridge does. Good luck with your choice.

 

[matt2143]

Yea my Bartlein barrel pushes factory M118LR 75 fps fast than my 21" factory Remington barrel and not much slower than my 24" HS precision HTR.

 

[Lafayette]

wow 178s running at 2750 from 20" gave me goosebumps.. I run both a 20" and 26" sweet spot for me on the 20" was about 2550 and 2690 out of the 26"

Im in a similar boat in looking at 7-08 vs .260/6.5cm but I want a longer barrel (don't shoot suppressed)...

Any recommendations for me? Im leaning 7mm-08 - I like the security of having match factory ammo if I want to push off reloading at any given time

 

[BoilerUP]

Any recommendations for me? Im leaning 7mm-08 - I like the security of having match factory ammo if I want to push off reloading at any given time

There's no such thing as 7mm-08 factory match ammo.

 

[sierracharlie338]

7-08 gets my vote. I like the ballistics better for over 1000. Either would come close to cutting wind drift by half over the 308.

 

[Lafayette]

There's no such thing as 7mm-08 factory match ammo.

Hornady Manufacturing Company :: Ammunition :: Rifle :: Choose by Caliber :: 7mm-08 Rem :: 7mm-08 Rem 139 gr SST® Superformance®

 

[jfields]

Yea I am running 178 BTHP's at 2750 over 47 grains of PP2000MR in LC brass with Fed 210 primers. Bumping the shoulders back .004" with an overall to ogive of 2.220" and COAL somewhere around 2.9xx". Since I am using AW length mags I can load out to 2.974".

I will be loading up some 178 AMAX and 178 BTHP over Varget this weekend for testing with CCI 200 and Fed 210 primers. We will see what this gun really likes.

I will be really surprised if you get more velocity out of Varget. I do not have any experience with 2000MR (Always wanted to try it), but I do with Varget and RL17. The fastest I can send a 178 AMAX safely out of a 20" Krieger is 2700 FPS. That is 49.2 grains of RL17. I could never get close to that with Varget. If you are already sending the higher BC BTHPs at 2750, you may have the best short barrel load ever. I wouldn't change a thing.

-J

 

[Emouse]

49.2grs????

Surely thats a seriously compressed load and with RL17 and then not very efficient especially in such a short tube (muzzle flash must be awesome!)

RL17 works very well in the 6.5 and long barrels (very effecient and very very fast) but why restrict yourself to short tubes and try to push things at breakneck speed?

I shoot the 178gr AMAX over RL15 @2600fps with 43.3grs 26" tube. It works,..sub MOA and doesn't toast the barrel. Do you think RL17 really is worth running with a 178 as my experience shows its not the correct powder in that bullet weight/size??