Float Pilot
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Chamber your short action in 358 Win or 338 Federal. Add some thump to your hunt.
Long range/short action
- Thread starter mshootnit
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Offfhand
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Mr. Taliv, thank you for effort in responding to my query in this thread, which was why you had stated that the 6.5cr has the "right" neck and the .260 Rem has the "wrong" neck. Since you did not address question specifically perhaps I did now state it clearly. So I'll put it another way: The neck length of the .260 is .259", and that of the 6.5 cr is .285' (using Hornady's figures) making the 6.5cr neck .026" longer than the .260. In fractional terms that is less than 1/32 of an inch. So how does this less than 32nd of an inch difference make the difference between "right" and "wrong" necks? Also in your reply you make reference to "flexibility in seating depth without having the back of the bullet pushed past the shoulder." Which is an interesting observation which you may care to expand on further. Thanks again for your help and effort.
perhaps this diagram will help. when your cartridge overall length is constrained by a magazine, such as the popular AICS (2.880") or AIAW (accuracy international pattern) magazines, then how far you can seat a bullet out into the lands, and how far the base of the bullet extends into the case interior past the shoulder junction is a function of the body and neck lengths.
as you can see, the 260rem has a relatively long body, and with a 20* shoulder, a long shoulder, which if you're single feeding, would mean you could seat the bullet out as far as you want and put more powder in the case to get more velocity. but if you're feeding from a magazine, that means you're seating the bullet very deep usually to the point on the bullet where the shank stops and the taper begins.
on the 6.5x47, it's a much shorter body, shorter shoulder, and a longer neck. it lets you seat the bullet out longer and gives you room to chase the lands as your barrel wears, if you're into that sort of thing.
Stony
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I recently rebarreled a Savage 16 into 6.5 Creedmore and have been tickled with it. I am not a long range shooter, but put a night scope on it for hog hunting. Just last week I ordered a batch of Hornady brass from Midway with no problem. So far components have been readily available, including factory ammo that I played with some.
a bit more math... the berger 140g hybrid that i shoot is 1.407" long.
the boattail is .224".
the bearing surface is .415"
the nose is .768
the 260rem case oal is 2.035"
the neck is .256"
the shoulder-neck junction is 1.776" from the base
the 6.5cm case oal is 1.920"
the shoulder-neck junction is 1.635" from the base
the AICS magazines I use can hold up to 2.880" OAL.
so... if i seat a bullet in 260rem to max length that will fit in the magazine,
that means with the bullet seated out as far as it will go, .562 of the bullet is inside the case, which means .306" of the bullet is sticking inside the case past the neck.
also, the back end of the bullet is .639" before it starts to taper in the front and that only leaves 0.077" of shank past the neck.
now that compares to the 6.5cm as follows: .447" of the bullet is inside the case, and .1618" past the case past the neck, but since the boat tail is .224, you're not wasting bearing surface.
i'll let you keep doing the rest of the math as i need to go do some work, but the next consideration is how much freebore you have.
the boattail is .224".
the bearing surface is .415"
the nose is .768
the 260rem case oal is 2.035"
the neck is .256"
the shoulder-neck junction is 1.776" from the base
the 6.5cm case oal is 1.920"
the shoulder-neck junction is 1.635" from the base
the AICS magazines I use can hold up to 2.880" OAL.
so... if i seat a bullet in 260rem to max length that will fit in the magazine,
that means with the bullet seated out as far as it will go, .562 of the bullet is inside the case, which means .306" of the bullet is sticking inside the case past the neck.
also, the back end of the bullet is .639" before it starts to taper in the front and that only leaves 0.077" of shank past the neck.
now that compares to the 6.5cm as follows: .447" of the bullet is inside the case, and .1618" past the case past the neck, but since the boat tail is .224, you're not wasting bearing surface.
i'll let you keep doing the rest of the math as i need to go do some work, but the next consideration is how much freebore you have.
so let me continue a bit, but make the statement a slightly different way. with the 6.5cm i can seat the bullet out so far that i only have .223" of neck-to-bearing surface contact, which is less than i would really want. in other words, i'd never seat a 6.5cm out so far that it wouldn't fit in an AICS magazine.
now, the gen m3 pmag that i would use in an SR25/AR10 style rifle only has a max OAL of 2.830, which is 50 thou less so i could still run out of room there, but i'm generally pretty comfortable with that.
but with the 260rem, if i wanted to seat the bullet so the bottom of the bearing surface was at the bottom of the neck, my cartridge OAL is 2.962, which is 82 thou longer than will fit in an AICS mag, and 152 thou longer than will fit in a PMAG.
that is usually the reason you will occasionally hear statements about the 6.5cm being better for gas guns.
also, the 260rem was originally more of a varmint/deer cartridge with smaller bullets. i don't think it's been until fairly recently that people have run them with tight twists and long target bullets.
now, the gen m3 pmag that i would use in an SR25/AR10 style rifle only has a max OAL of 2.830, which is 50 thou less so i could still run out of room there, but i'm generally pretty comfortable with that.
but with the 260rem, if i wanted to seat the bullet so the bottom of the bearing surface was at the bottom of the neck, my cartridge OAL is 2.962, which is 82 thou longer than will fit in an AICS mag, and 152 thou longer than will fit in a PMAG.
that is usually the reason you will occasionally hear statements about the 6.5cm being better for gas guns.
also, the 260rem was originally more of a varmint/deer cartridge with smaller bullets. i don't think it's been until fairly recently that people have run them with tight twists and long target bullets.
Howard Roark
Member
"i don't think it's been until fairly recently that people have run them with tight twists and long target bullets."
For the masses, yes. I built my first one in 2005. Sam Tedders was tearing up belly shooting down here with one and I had to jump on the bandwagon. Whidden was shooting a .243 on an AR-10. He shot the first 600 clean that I ever saw. Now, that's fairly common.
For the masses, yes. I built my first one in 2005. Sam Tedders was tearing up belly shooting down here with one and I had to jump on the bandwagon. Whidden was shooting a .243 on an AR-10. He shot the first 600 clean that I ever saw. Now, that's fairly common.
The 260 was Remington's late '90's commercial version of the 6.5x308 wildcat cartridge made popular in high power match rifle competition's top ranked shooters in the early 1990's. Mid Tompkins was probably more responsible than all the others.
When Sierra Bullets finally was able to get good jacket material that enabled 26 caliber, long, heavy 140-gr. bullets to be made with very uniform thickness, their accuracy finally equalled what they got with 30 caliber match bullets. Same problem they had with their 28 caliber match bullets starting in 1970 but finally fixed in the 1980's which led to the 7-08's popularity in competition.
The 6.5x284 soon followed shooting 26 caliber bullets out faster than the .260. It was the death knell for most belted magnums in long range prone matches. While equally as accurate as the best 28 and 30 caliber magnums and bucking the wind as well, its lesser recoil made rifles easier to shoot more accurate. They moved less while the bullets were going through the barrel minimizing the bullet's departure angle error. All of which is why someone who can call 20 shots inside 2/3 MOA but their stuff that tested 2/3 MOA resting on bags for 20 shots doesn't go inside 1-1/3 MOA on paper in perfect conditions. 2 or more MOA is more likely.
600-yard 20-shot cleans became frequent back in the late 1960's when the 308 Winchester replaced the 30-06 as "the" match rifle cartridge and the old military B target was replaced by the NRA MR (mid range) target. Too many unbreakable ties on the old B target (20" 5 ring, 12" V ring) is why the 1966 MR target scoring rings (12" 10 ring, 6" X Ring)were made smaller than what the B target had.
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Offfhand
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Mr. Bart B is absolutely correct about the .260 Rem. beginning life as a target cartridge. First known as the wildcat 6.5 Panther it was developed by a well known Silhouette/ High power shooter. Later adopted by Remington and renamed .260, it earned its current reputation as superb hunting round. It's reputation and popularity as a target round was crowned in 2010 by female shooter Sherri Gallager when she won the National High Power Championship using a .260 rifle to set a new course record.
Txhillbilly
Member
Taliv,The 260 Super L/R has all those features if you want to use 308 Palma brass.
http://www.6mmar.com/65_SuperLR.php
I like all 6.5mm cartridges,I shoot a 6.5 Creedmoor,260 Remington,6.5x6.8,and 6.5-06. I have a 260 AI barrel just waiting to go onto an action setting in the closet,as well as another 6.5 Creedmoor barrel.
While Hornady 6.5 Creedmoor brass has had primer pocket issues,the Nosler brass has been great.
I use resized 243 Winchester brass with my 260 since it is an AR platform that I use for hunting,and I don't care if I loose the brass in the field.
I have more brass issues out of my 6.5x6.8 wildcat than I've ever had with the Creedmoor. 6.8 SPC brass sucks!
I've got some Lapua 260 brass that I'll fire form in the 260 AI barrel,but I've never seen much advantage in their brass over other brands in the cartridges that I shoot.
I don't shoot factory ammo,so that's a moot point to me. People can argue which 6.5mm cartridge performs better,it all depends on what you want to obtain with your shooting.
http://www.6mmar.com/65_SuperLR.php
I like all 6.5mm cartridges,I shoot a 6.5 Creedmoor,260 Remington,6.5x6.8,and 6.5-06. I have a 260 AI barrel just waiting to go onto an action setting in the closet,as well as another 6.5 Creedmoor barrel.
While Hornady 6.5 Creedmoor brass has had primer pocket issues,the Nosler brass has been great.
I use resized 243 Winchester brass with my 260 since it is an AR platform that I use for hunting,and I don't care if I loose the brass in the field.
I have more brass issues out of my 6.5x6.8 wildcat than I've ever had with the Creedmoor. 6.8 SPC brass sucks!
I've got some Lapua 260 brass that I'll fire form in the 260 AI barrel,but I've never seen much advantage in their brass over other brands in the cartridges that I shoot.
I don't shoot factory ammo,so that's a moot point to me. People can argue which 6.5mm cartridge performs better,it all depends on what you want to obtain with your shooting.
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