308 win 3000fps?

[BuddhaMonkey]

I'm a shooter but not a reloader. I have been considering taking up reloading to hop up my sniper rifle. I just picked up a tactical 308 with a 26" bull barrel w/ 1/10" twist. Can I safely get another 200-400 fps with custom loads? ,150-168gr) I'd like to see 3000+ fps, but not sure if it's worth the trouble or safe.

Thanks
BM

 

[billmo]

I have safely chrono'd 150 gr. Nosler BT CT Bullets at over 3100 fps many times from a Rem Police Rifle with a 26" barrel. Most Remington .308s have very long freebore or throats which most of the time will allow you to seat your bullet out towards the lands and therefore free up some space in the case. NOTICE I DID SAY MOST OF THE TIME. Some of the .308 MIL-SPEC 24" barrel rifles that Rem. made special runs of did not have extra long throats and I believe they had 1 - 9 or 1 - 10 twist also and this was an exception as I'm sure there are others. Hope this helps. Bill

 

[Ksmirk]

BM, My rifle I have been getting 2770 from the 168 SMK's from a 26" 1-14 twist Parker Hale barrel. I have the COAL set at 2.810" and I'm sure I could get a bit more from it but the load just shoots too well and if I go over this to get the velocity the accuracy goes South. I'm sure you could get the 155 Palma bullets real close or at 3K but an accurate load is not always fast and for LR it does not have to scream it just has to hit where you dope it. Lots of range time would be the better than 3K. Later,

Kirk

 

[billmo]

That is exactly right and a very good point. I have run 150 gr. bullets well over 3000 in the past. Some were accurate and some not. The good thing about slowing them down is barrel life. But that all boils down to whatever floats your boat. Thanks, Bill

 

[chadjamesr]

I just returned from the range in Orlando,85 degrees) and was shooting 168gr Nosler J4 bullet at 2850 with 46 gr of Varget and Winchester brass. My rifle has a 24" 1-10 twist Lothar Walther LW50 barrel. It is starting to show pressure signs though but accuracy is not suffering. Hopefully this give you some idea of what is possible.

 

[billmo]

Yea Chad, with that twist and barrel length you are doing well.
Probably would not show any pressure in cooler temps or you may want to trim it up a bit. The tighter twist and 24" pipe will be
a little slower than say a 1-12 26" or at least that has been my experience. Others may differ. Thanks, Bill

 

[billmo]

Donovan, the two rifles that I was working with at the time were a Rem SV with a 26" barrel 1-12 twist and a Rem Mil-spec with a 24" barrel 1-9 or 1-10 twist with the 26" being faster. On my P-35 I saw about 150 fps or better difference with the same loads but my seating depth was different as you might expect. 150 gr. BT CT bullets will usually be a little faster anyway and that is what I was loading at the time. I could dig up some old paperwork and get you specific numbers if you would like. Thanks, Bill

 

[billmo]

It may not be all twist related since the barrel lengths were different. I have never compared the same twist with the same length barrel. And all my knowledge has come from actually shooting. Not from any kind of computer program. So, I'd be out of turn if I said I knew how much difference that changing only the twist would affect the MV. Sorry, if I mis-led you. Thanks, Bill

 

[billmo]

O K Fair enough. Your thoughts. Could some other shooters weigh in on this issue. I am curious now that the subject is up and running just how much difference twist does make?????? Thanks, Bill

 

[Ksmirk]

One trick to the twist issue unless you wanted computer or mathematical results would be to find 2 barrels of the same bore and groove, there are many variables that would have to be controlled to get real results to compair for exacting results. Now I'm sure that you could get close but just this guys opinion the difference would not be enough for the argument and work involved to figure out the results! granted there would be a difference between 1-10, 1-12, 1-14 twist barrels due to the effect of friction on the bullet but to get the variables all equal would be the biggest test.

Now the question is why do you need to get 3K from a 308? if this is a question about a caliber choice go with a larger 30cal would be the easiest way to drive a bullet to those speeds with much less strain on your components, if this is just a "Can I do it" question then yes you can but why? I shoot my load out to 1K and it works very well when I can get all things figured out and the wind is not doing to many different things Later,

Kirk

 

[billmo]

Kirk, I have no clue. That would be a question for the originator of this thread. Thanks, Bill

 

[memilanuk]

Donovan,

My understanding is that its kind of a 'conventional wisdom' sort of thing, which doesn't necessarily mean it's at all correct,or wrong either). With a faster twist rate supposedly a bit of the energy for pushing the bullet forward is diverted to the purpose of spinning it faster, which would make it a little harder to push it as fast, all else remaining equal.

Since 'all else' rarely ever remains equal, it's probably something that is hard to pin down via empirical testing as there will always be some question as to the 'equal' factor. Since this came to me through people who have burned their way through way more .308 barrels than I have, I tend to give at least some degree of credence, if only because I can't necessarily *disprove* it.

Kirk,

3000fps, or close to it,more like 2950-2975, +/- 25fps either way) is fairly normal for people shooting a 155gr bullet in Palma, TR, or F/TR. I've done it with 26" factory barrels in the past; it's certainly doable though the loads may be warmish. A custom barrel of that length shouldn't have too much problem. The 'traditional' 30" tube for this application isn't strictly necessary in my mind, but it does make it possible to get there without having to push things as hard.

YMMV,

Monte

 

[memilanuk]

Donovan,

From a functional view point, you're right... I've managed to hit similar velocities out of barrels with twists from 10 to 13 without too much problem. There was some noticeable difference in charge required, but as mentioned... it could have been as much due to individual differences in the barrel as much as the twist rate.

I guess it comes down to, for me, if I had a goal of shooting a 155gr @ 2950-3000fps... a 10 twist probably wouldn't be my first choice. I know people that have done it quite successfully, so it's not a question of whether it works or not. It just doesn't appear to be the best answer to the question in general.

To each their own,

Monte

 

[billmo]

Besides for mathematical/ballistic knowledge of understanding that the Velocity and Energy looses are minimal to nil, I have shot similar configured barrels in 6mm/.243 from 8-twist up to 12-twist and have never seen a "slow down effect" that is being alluded to.
Of course there is some differences, but to favor no one direction to the Rates of Twist, one way or the other. Just normal variances from one barrel to the next.
What I have seen that is some what noticeable, is Velocity variance from "bore diameters". Not enough to sneeze much at, but maybe up to 30-fps or so in one circumstance.

But to tell someone that they will loose Velocity by going with a "faster rate of twist" won't hold much water.....in my opinion.



Dmoran, Please read my post again.
If you read my whole post, you will understand that I was including the fact that the barrel was 2" shorter on the Mil-spec rifle and that I also stated that bullet seating depths were different. The WHOLE picture clearly paints the difference that I saw while shooting the two rifles. No need to make this argumentive. I just simply said what my experience was and no more or no less. It's your choice to focus on your experience but don't try to make mine sound stupid or inaccurate. Thanks, Bill


Happy Shooting
Donovan Moran

 

[billmo]

Milanuk, I was using the same load components and same amount of powder in both rifles which would cause more of a difference than you saw because of varying amounts of powder. Thanks, Bill

 

[Rustystud]

The original Post 308 at 3000fps. First let me say the 150 grain Hornaday light magnums advertise at 3000fps. Most other brands of factory ammo advertise 2850-2900fps.

I reload and 3000 fps is a easy reality with 110-130 grain bullets.

The Hornaday Light Magnums are a propriatary compressed duplex load.

I tested with W748 ball powder because it was the fastest burning and most dense powder. All the reloading manuals max out at 47 grains of W748. Do not try this without working up your loads first. I currently am loading W748 in LC Match Brass with Federal 215GMM primers, behind 150 SciroccoII. Yes, it shows presure signs, It shoots 3019fps, subb .5 at 100yds out of a Remington model 7, with 20" barrel.

3000 fps can be acheived in a 308. Palma shooters shoot 155s out of 30" tubes all day.

Rustystud

 

[billmo]

Yea Chad, with that twist and barrel length you are doing well.
Probably would not show any pressure in cooler temps or you may want to trim it up a bit. The tighter twist and 24" pipe will be a little slower than say a 1-12 26" or at least that has been my experience. Others may differ. Thanks, Bill

Above is the post that I Replied to ..... and what I questioned, and gave my OPINION and EXPERIENCE that "Rate of Twist" does not have any significant effect on Velocity.... This opinion is also proven in mathematical ballistic's.

Donovan

And I never said definitely that it did ALONE. But I was refering to the combination of several factors and replied earlier in the thread that I WOULD BE OUT OF TURN TO SAY I KNEW HOW MUCH THE TWIST FACTOR WOULD CHANGE MV. But,I personally believe all other things being equal if that were possible that it would make some difference. Your opinion expressed and mine also. Bottom line. We need to move on. Thanks, Bill

 

[billmo]

Prove it MR. BALISTICS EXPERT.

 

[billmo]

Correction. Read it again. I had more differences than twist with my two rifles. I said that was my experience and others may differ. I never said "YOU WILL LOSE MV BY CHANGING TWIST ALONE"
I also made a single statement saying that I would be out of turn by making that statement. You need to review the whole thread.

I enjoy reading your post as well. I simply don't want to be thought of as someone just typing a conversation. If I have no experience in whatever is being asked about, then I will refrain from any opinions. And, that was only my opinion based on the two rifles that I happened to be playing with at the time. It was not planned. I just payed attention to what I was seeing on the chrono. Not proven facts. Best of all shooting experience to you too. Thanks, Bill