308 Win w/ Win 748 & 230gr

yankytrash · May 10, 2001, 04:50 AM

I've got quite a bit of Winchester 748 around here. I normally load my 308's with 3031, but I'd like some load data using 748.

I'm using FMJ BT 230gr bullets.

While you're here, load data for the 30-06 with the same materials would be nice.

Thanks

WARNING TO ALL READERS OF THIS THREAD:

THERE MAY BE REPLIES IN THIS THREAD THAT ARE NOT RECOMMENDED FOR MOST GUNS. ALWAYS START WITH MINIMUM LOADS WHEN USING NEW LOADS. INJURY OR DEATH MAY OCCUR IF IMPROPER LOADS ARE USED.

echo3mike · May 10, 2001, 08:20 AM

I really wanted to help with this, since I'm starting to load some .308 w/168gr HPBT MK for target loads, but I don't have the data in either Sierra's 4th Ed or Speer's 13th Ed for a 230gr .308 dia. bullet. In fact, I've never seen that weight in a .308 bullet, but I haven't seen much, yet.

With the 748, the heaviest bullet wt used in ethier reference was the 190gr for the 30.06 and the .308. The .308 has a range of 39.4gr (2300fps) to 45.5gr, (max load, 2600fps). The 30.06 had ranges of 39.9gr, (2300fps), to 46.0gr, (max load, 2500fps). (Both from Sierra, using their 190gr HPBT MK).

I noticed the burn rate for 748 is listed as being faster than 3031, 4064, and 4895, (the powders I'm familiar with). Are you getting high pressure signs with the loads you're using now?

I'ld recommend, (from my VAST knowledge of reloading

)that you give the Sierra tech line a call, (1 800 223-8799), 0800-2200 central, to confirm this potential load as being a safe option. Let us know what they say.

Poodleshooter · May 10, 2001, 10:14 AM

Methinks you have your bullet weights mixed up. 230gr sounds more like .45 auto. Perhaps you meant 150gr? Anyway, go to the Winchester ammo home page and print up their powder data from there. A search online should find it easily.

Cheapo · May 10, 2001, 11:53 AM

I might be able to look up 220-gr info for you. Sierra makes a 240, but it's not suitable for most .308s. Twist rate/velocity becomes the limiting factor.

Otherwise, 748 works great. Wish I could affort a keg of it!

yankytrash · May 10, 2001, 01:07 PM

Yes, that's what I said. 230 grain. Most of the cases are Hornady(about 45 boxes left). I also have 10 boxes of 230gr Speer SP BTs.

You just gotta keep a good eye out at the shows, you'll find'm. Hell, I've come across 260 gr FMJ .308".

Now, back to the question....

yankytrash · May 10, 2001, 08:14 PM

Whew! Been all over the net today and came up empty. Most load data only goes up to 200gr, and most seem to switch from 748 to 760 on the heavier bullets.

So it was back to the books. Here's what I'm gonna try...

Most of my old books all seem to list 748 in decreasing charges as bullet weight goes up. Doesn't really make a lot of sense to me, but I guess maybe they're try'n to up the chamber pressure on the heavier bullets. Or maybe they're slowin'm down a little to get a twist.
Anyway, I notice the charges seem to have a pattern. For every 30 grains of bullet weight, the charge of 748 goes down, on average, 2 grains (at max loads).
Since I have load data for 308/748 up to 200gr, I think I'm goona "bite the bullet", and try it. I hope I don't have to eat those words, both figuratively and literally.

My first batch will be 40 grains of 748. I'm basing my data against Lyman's 46th, which has seemed to suit me well over the years. 40 grains falls well within the middle charge of all jacketed bullets from 180-200.

Wish I had a chronometer and all that other fancy crap now.

Paul B. · May 12, 2001, 01:35 AM

Yankeetrash. According to data I have, your load of 40.0 gr. of W-748 is too hot. If you want it, I have data for 220 gr. bullets will will give you a better idea of where to go. I don't post loads on forums, so you'll have to E-mail me for the data.
I may be going out of town for a few days, so don't panic. I will get back to you.
Paul B.

**Bud Helms** · May 12, 2001, 08:28 AM

yankytrash,

Before you go to the range, I'd like a drive-out price on all your reloading equipment.

W748 is not the best powder for a 230 gr bullet in .308, not by a long shot. I noticed this ...

Quote:

Most of my old books all seem to list 748 in decreasing charges as bullet weight goes up. Doesn't really make a lot of sense to me, but I guess maybe they're try'n to up the chamber pressure on the heavier bullets. Or maybe they're slowin'm down a little to get a twist.

The charge weight of the powder decreases as the bullet weight increases in order to keep the pressure at a safe level, all other things remaining the same. If they wanted to "up the chamber pressure", they would just leave the charge the same and increase the bullet weight ... or leave the bullet weight the same and increase the powder charge. That's not what they are trying to do. Run the pressure up is not the objective of any load. Run the velocity up, maybe. But without exceeding pressure limits.

One other thing. You can't "get a twist" with a load variation. The twist is manufactured into the bore of the barrel. If you think have all this down, then go back and read your post again. For your own safety, get back in the books. Get a working understanding of pressure vs momentum with modern progressive powders. Pay particular attention to the firing cycle, from primer strike through muzzle exit.

Don't be offended, I have only your post to judge your understanding of the pressures and their causes. Maybe you mistyped. Best of luck.

Zak Smith · May 14, 2001, 12:01 AM

To be particular, bullet stabilization is a function of bullet RPM, not only twist rate. rotational rate = muzzle velocity * twist rate.

For example, if you have a load that is understabilized and keyholes through the target, you need to increase the rotational rate of the bullet. One way to do this is obviously to increase the twist of the barrel. The other way is to increase the muzzle velocity. If you are already close to the maximum load, this is not an option, but in some cases it is.

When a bullet is understabilized, it actually means that the angular momentum is too low, as compared to the force on the bullet from airflow (denser air and longer bullets increase this force). One way to increase the angular momentum while not changing bullet mass is to move the distribution of mass away from the axis of rotation: this can be true in HP's and ballistic tips vs. regular spire points; and more blunt-pointed bullets will have a larger rotational inertia value than the same mass spire point.

To reduce the angular momentum requirement, reduce the torque the atmosphere acts on the bullet by reducing air density (the force component) or by reducing the bullet length (the radius-length component).

Rotational velocity is lost at a slower rate than linear velocity, so a bullet will become more stable as it flies -- however, since the rotation keeps the bullet pointing the direction is started off pointing, the force of air on the tip of the bullet working to destabilize it increases as the path of the bullet diverges from the direction it is pointing. This is why marginally-stabilized bullets will keyhole after a certain distance, not right away.

This is merely a brief qualitative discussion, but I think the basics are correct.

-z

yankytrash · May 15, 2001, 04:59 AM

Went to my range this past weekend with the new load. Let me say this - WOW!
Those loads were more consistent than I've shot out of my M14 in a long time! Normally, with the 3031, I'd get an occasional wild shot that'd almost completely miss the target paper. With this new load, I was hittin a 1 1/2" pattern at 250 yds all day long.

It got me to thinkin of grabbin that chainsaw and throwin in another 50 yards on the range....

Zak Smith · October 9, 2001, 07:01 PM

FWIW, the Hodgdon and Barnes books list data for 220gr bullets.

Hodgdon, starting point, 220gr, commercial cases:
H4831 44.0
H4350 43.0
H414 42.0
H380 41.0
BLC2 38.0
H335 35.0

Decrease 2gr for USGI cases.

Barnes 220gr data, starting point:
H380 40.5
H414 41.0
IMR4064 33.0
IMR4350 40.0
AA2460 35.5
RL15 35.5

Barnes 250gr data, starting point:
H380 38.0
H414 39.0
IMR4064 31.0
IMR4350 39.0
AA2460 32.0
RL15 34.0

Check current versions of those books to make sure..

-z

Johnny Guest · October 10, 2001, 10:32 AM

Sure sounds as if you're on the right track.

Also sounds as if you have an exceptional rifle to hold that tight a group at 250 yards. You mentioned using an M14. Is it really one of those, or an M1-A? In any case, the very heavy bullets can sure beat up an autoloader if the pressure curve is not just right.

I strongly suggest you get on the technical assistance help line at Sierra and talk with them about loads for their long heavy bullets. I've found them to be very knowledgeable and helpful. Sorry i don't' have the number at hand, but you can get it from their web site or their manual.

Best of luck,
Johnny

May 10, 2001, 08:20 AM	#2
echo3mike Senior Member Join Date: September 12, 2000 Location: Chantilly, VA...Just barely behind the lines! Posts: 490	uhm... I really wanted to help with this, since I'm starting to load some .308 w/168gr HPBT MK for target loads, but I don't have the data in either Sierra's 4th Ed or Speer's 13th Ed for a 230gr .308 dia. bullet. In fact, I've never seen that weight in a .308 bullet, but I haven't seen much, yet. With the 748, the heaviest bullet wt used in ethier reference was the 190gr for the 30.06 and the .308. The .308 has a range of 39.4gr (2300fps) to 45.5gr, (max load, 2600fps). The 30.06 had ranges of 39.9gr, (2300fps), to 46.0gr, (max load, 2500fps). (Both from Sierra, using their 190gr HPBT MK). I noticed the burn rate for 748 is listed as being faster than 3031, 4064, and 4895, (the powders I'm familiar with). Are you getting high pressure signs with the loads you're using now? I'ld recommend, (from my VAST knowledge of reloading )that you give the Sierra tech line a call, (1 800 223-8799), 0800-2200 central, to confirm this potential load as being a safe option. Let us know what they say. __________________ God, Country, Corps! "Only Accurate Rifles Are Interesting" Col. Townsend Whelen Por Libertate Patriae TFL Alumni

May 14, 2001, 12:01 AM	#9
Zak Smith Senior Member Join Date: December 12, 1999 Location: Fort Collins, Colorado, USA Posts: 2,682	Twist. To be particular, bullet stabilization is a function of bullet RPM, not only twist rate. *rotational rate = muzzle velocity twist rate*. For example, if you have a load that is understabilized and keyholes through the target, you need to increase the rotational rate of the bullet. One way to do this is obviously to increase the twist of the barrel. The other way is to increase the muzzle velocity. If you are already close to the maximum load, this is not an option, but in some cases it is. When a bullet is understabilized, it actually means that the angular momentum is too low, as compared to the force on the bullet from airflow (denser air and longer bullets increase this force). One way to increase the angular momentum while not changing bullet mass is to move the distribution of mass away from the axis of rotation: this can be true in HP's and ballistic tips vs. regular spire points; and more blunt-pointed bullets will have a larger rotational inertia value than the same mass spire point. To reduce the angular momentum requirement, reduce the torque the atmosphere acts on the bullet by reducing air density (the force component) or by reducing the bullet length (the radius-length component). Rotational velocity is lost at a slower rate than linear velocity, so a bullet will become more stable* as it flies -- however, since the rotation keeps the bullet pointing the direction is started off pointing, the force of air on the tip of the bullet working to destabilize it increases as the path of the bullet diverges from the direction it is pointing. This is why marginally-stabilized bullets will keyhole after a certain distance, not right away. This is merely a brief qualitative discussion, but I think the basics are correct. -z

October 10, 2001, 10:32 AM	#12
Johnny Guest Moderator in Memoriam Join Date: August 28, 1999 Location: North Texas Posts: 4,123	yankytrash - - - Sure sounds as if you're on the right track. Also sounds as if you have an exceptional rifle to hold that tight a group at 250 yards. You mentioned using an M14. Is it really one of those, or an M1-A? In any case, the very heavy bullets can sure beat up an autoloader if the pressure curve is not just right. I strongly suggest you get on the technical assistance help line at Sierra and talk with them about loads for their long heavy bullets. I've found them to be very knowledgeable and helpful. Sorry i don't' have the number at hand, but you can get it from their web site or their manual. Best of luck, Johnny

May 10, 2001, 04:50 AM	#1
yankytrash Senior Member Join Date: April 17, 2001 Location: Farnham, Va Posts: 2,183	I've got quite a bit of Winchester 748 around here. I normally load my 308's with 3031, but I'd like some load data using 748. I'm using FMJ BT 230gr bullets. While you're here, load data for the 30-06 with the same materials would be nice. Thanks WARNING TO ALL READERS OF THIS THREAD: THERE MAY BE REPLIES IN THIS THREAD THAT ARE NOT RECOMMENDED FOR MOST GUNS. ALWAYS START WITH MINIMUM LOADS WHEN USING NEW LOADS. INJURY OR DEATH MAY OCCUR IF IMPROPER LOADS ARE USED.

May 10, 2001, 10:14 AM	#3
Poodleshooter Senior Member Join Date: August 7, 2000 Location: Floating down the James River in VA Posts: 2,599	Methinks you have your bullet weights mixed up. 230gr sounds more like .45 auto. Perhaps you meant 150gr? Anyway, go to the Winchester ammo home page and print up their powder data from there. A search online should find it easily.

May 10, 2001, 11:53 AM	#4
Cheapo Senior Member Join Date: November 19, 1998 Posts: 986	I might be able to look up 220-gr info for you. Sierra makes a 240, but it's not suitable for most .308s. Twist rate/velocity becomes the limiting factor. Otherwise, 748 works great. Wish I could affort a keg of it!

May 10, 2001, 01:07 PM	#5
yankytrash Senior Member Join Date: April 17, 2001 Location: Farnham, Va Posts: 2,183	Yes, that's what I said. 230 grain. Most of the cases are Hornady(about 45 boxes left). I also have 10 boxes of 230gr Speer SP BTs. You just gotta keep a good eye out at the shows, you'll find'm. Hell, I've come across 260 gr FMJ .308". Now, back to the question....

May 10, 2001, 08:14 PM	#6
yankytrash Senior Member Join Date: April 17, 2001 Location: Farnham, Va Posts: 2,183	Whew! Been all over the net today and came up empty. Most load data only goes up to 200gr, and most seem to switch from 748 to 760 on the heavier bullets. So it was back to the books. Here's what I'm gonna try... Most of my old books all seem to list 748 in decreasing charges as bullet weight goes up. Doesn't really make a lot of sense to me, but I guess maybe they're try'n to up the chamber pressure on the heavier bullets. Or maybe they're slowin'm down a little to get a twist. Anyway, I notice the charges seem to have a pattern. For every 30 grains of bullet weight, the charge of 748 goes down, on average, 2 grains (at max loads). Since I have load data for 308/748 up to 200gr, I think I'm goona "bite the bullet", and try it. I hope I don't have to eat those words, both figuratively and literally. My first batch will be 40 grains of 748. I'm basing my data against Lyman's 46th, which has seemed to suit me well over the years. 40 grains falls well within the middle charge of all jacketed bullets from 180-200. Wish I had a chronometer and all that other fancy crap now.

May 12, 2001, 01:35 AM	#7
Paul B. Senior Member Join Date: March 28, 1999 Location: Tucson, AZ Posts: 3,802	Yankeetrash. According to data I have, your load of 40.0 gr. of W-748 is too hot. If you want it, I have data for 220 gr. bullets will will give you a better idea of where to go. I don't post loads on forums, so you'll have to E-mail me for the data. I may be going out of town for a few days, so don't panic. I will get back to you. Paul B.

May 15, 2001, 04:59 AM	#10
yankytrash Senior Member Join Date: April 17, 2001 Location: Farnham, Va Posts: 2,183	Went to my range this past weekend with the new load. Let me say this - WOW! Those loads were more consistent than I've shot out of my M14 in a long time! Normally, with the 3031, I'd get an occasional wild shot that'd almost completely miss the target paper. With this new load, I was hittin a 1 1/2" pattern at 250 yds all day long. It got me to thinkin of grabbin that chainsaw and throwin in another 50 yards on the range....

October 9, 2001, 07:01 PM	#11
Zak Smith Senior Member Join Date: December 12, 1999 Location: Fort Collins, Colorado, USA Posts: 2,682	FWIW, the Hodgdon and Barnes books list data for 220gr bullets. Hodgdon, starting point, 220gr, commercial cases: H4831 44.0 H4350 43.0 H414 42.0 H380 41.0 BLC2 38.0 H335 35.0 Decrease 2gr for USGI cases. Barnes 220gr data, starting point: H380 40.5 H414 41.0 IMR4064 33.0 IMR4350 40.0 AA2460 35.5 RL15 35.5 Barnes 250gr data, starting point: H380 38.0 H414 39.0 IMR4064 31.0 IMR4350 39.0 AA2460 32.0 RL15 34.0 Check current versions of those books to make sure.. -z