I wonder how many people consider the twist when buying a 308. It seems that the majority of 308 hunting rifles sold at present have a 1 in 10 twist which is good for 165 grain and above bullets, where as a 1 in 12 twist is better for lighter weight bullets. If you shoot a 7.5 lb rifle the recoil energy is 15.8 lbs with 150 grain bullets and 18.1 lbs with 165 grain bullets (i.e the lighter the bullet weight the less recoil energy). I think the reason that the 1 in 10 twist is used is because the same twist is usually used for 3006, 300 Winchester mag and 300 Winchester Short mag, so it is more economical for the manufacturers to use the same twist (i.e maybe the same mandrel is used when hammer forging the barrels?). I believe Browning and Winchester (i.e same manufacturer) still use a 1 in 12 twist while most others use a 1 in 10 twist (Sako and Tikka use a 1 in 11 twist for the 308). It is not to say you cannot shoot lighter weight bullets with a 1 in 10 twist, it is just that it will not be as accurate. It would seem logical to consider the twist if you intend to shoot lighter weight bullets in a 308. I find it interesting that Remington uses a 1 in 10 twist with their hunting rifles, but a 1 in 12 twist with rifles like the LTR and offers 1 in 14 twist in custom shop rifles. The reason I ask this is because I never did until recently (i.e ignorance is bliss!)
Did you consider the twist when you bought a 308 rifle?
- Thread starter rhino62
- Start date
In my experience and from what I've read you can't overstabilize a bullet in other words a faster spin than needed will not decrease accuracy. I dunno... maybe if you have a 1 twist in 1 inch or something radical that theory goes but within reasonable limits its not an issue. My last 10 twist 308 shot 150 grain bullets very well as did it 180. My 9 twist 223 shoots 75 grain bullets very well and, 45 grainers very well too.
There's been a lot said about twist rate and a lot of it is conjecture and myth.
I believe that: you can understabilize a bullet, but not overstabilize it; that the faster twists do not measurably increase pressure, nor decrease MV; and that more twist than "required" does not necessarily harm accuracy.
All said, in the 30 cal bore, I have shot from 100 gr to 220 gr bullets with good effect in 1:10 twist barrels.
I believe that: you can understabilize a bullet, but not overstabilize it; that the faster twists do not measurably increase pressure, nor decrease MV; and that more twist than "required" does not necessarily harm accuracy.
All said, in the 30 cal bore, I have shot from 100 gr to 220 gr bullets with good effect in 1:10 twist barrels.
I can hit a barn door, provided it is sunny!
- Location
- Southern Vancouver Island
It ain't hard to over stabilize a bullet, as in loading up 110 gr. jacketed hollow points in a .350 Remington mag. and pushing them to 3200+ fps. They generally come apart midway to a 100 yd. target. Fun to see though because of the tell-tail ring of lead dust they leave in the air. Hit a small critter inside of 30 yds. with that load and you basically have contact explosive.
Wabbit go poof!
A fast twist barrel can shoot light (i.e. short) bullets better than a slow twist barrel can shoot heavy (i.e. long) bullets. Provided that the bullet is stable, rifling twist is almost always a non-issue.
I have shot 40 grain bullets out of an AR with a 1:7 barrel just to test this. There were no issues with inaccuracy or bullet failure.
I have shot 40 grain bullets out of an AR with a 1:7 barrel just to test this. There were no issues with inaccuracy or bullet failure.
Over stabilization is not good, so one should not buy a fast twist barrel if the intention is to never shoot heavy bullets.
There are several barrels situations that can result in under stabilized bullets (tumbling). 22-250 barrels are still supplied in 1:14 or 1:12, whereas this caliber really sings with 75 and 80 gr bullets - that won't work with a 1-14. I think all 22-250s should come with 1:9.
I have a 1:14 222Rem. The heaviest bullet I can use in it for deer is the Sierra 62gr Semi-spitzer.
I use a lot of 1:14 and 1:13 barrels in 308 and they handle up to 180 gr just fine. If I was building a dedicated hunting rifle I would use 1:12 to allow for cold weather and a shorter barrel. (Lower velocity = lower RPM = lower stability.)
There are several barrels situations that can result in under stabilized bullets (tumbling). 22-250 barrels are still supplied in 1:14 or 1:12, whereas this caliber really sings with 75 and 80 gr bullets - that won't work with a 1-14. I think all 22-250s should come with 1:9.
I have a 1:14 222Rem. The heaviest bullet I can use in it for deer is the Sierra 62gr Semi-spitzer.
I use a lot of 1:14 and 1:13 barrels in 308 and they handle up to 180 gr just fine. If I was building a dedicated hunting rifle I would use 1:12 to allow for cold weather and a shorter barrel. (Lower velocity = lower RPM = lower stability.)
I think it's wonderful for those that are knowledgeable and make a study of the finer points ie twist, bullet weight, powder types and loads to gain the best of the best in accuracy, trajectory, velocity and so on. I think those of us who do this are true gun hobbiests (sp?) and many of whom also being hunters. Me, I fall only into the latter category and mostly own only .30 cal. rifles, (except for my Deerfield and a couple of.22s.) and have never given much thought to MOA. If I can do 2 inches with a scope at 100 yds and 2 inches with open sight at 50 I'm as happy as a pig in poop. The correct lead on a loping deer or up the inside front leg to a point half way up the body of a moose is what's important to me. I have 4 moose and lost track of the number of deer and am looking forward to next fall.
MapleSugar
CGN Ultra frequent flyer
- Location
- On the loose from NIMH
I read an article about 25 years ago where the author was praising the .308 Win as one of the most accurate cartridges ever.
FWIW, he claimed that his most accurate rifles all had a 1 in 12" twist rate.
FWIW, he claimed that his most accurate rifles all had a 1 in 12" twist rate.
I understand what you are trying to say there ronecol, but there is only so much my mind can retain with
the this and that and that and this.
Hence, only two powders I use regularly.
And I to appreciate the 30 caliber shooters.
Plus a kupple a wee bit bigger and a few pet wee'er ones.
the this and that and that and this.
Hence, only two powders I use regularly.
And I to appreciate the 30 caliber shooters.
Plus a kupple a wee bit bigger and a few pet wee'er ones.
Northman999
CGN Ultra frequent flyer
- Location
- Southern Yukon
I specifically look for 1:10 twist as I like heavy bullets and never had a problem with lighter ones using 1:10. Do I really "need it", I don't know, but apparently people who know more about it than me reccomend it for 210 gr vld's etc.
