Building a 308. Winchester Load

[The Grand Baboon]

Howdy guys, I have a question. I shoot a Remington 700 SPS in 308. and for some time now I've been using 150 gr Nosler Ballistic Tips for hunting. As per some recommendations I'm going to try the 180 gr Nosler instead but...

the 180 gr Nosler is much, much longer than the 150 gr. Long enough that I fear that I'm going to crush powder if I try to make it fit in my magazine.

What powders do I have available that would take up less volume (so I could seat the bullet at least somewhat deeper) and give me a velocity decent enough for hunting?

 

[rcmodel]

Well, I see in my Lyman #49 load manual that you can load a 200 grain Sierra HPBT using 4895, 4064, Varget, AA2520, 4320, N140, RX15, and N150 to max without compressed charges.

Maybe your load manual could tell you what will load to max with 180's without being a compressed charge?

rc

 

[Kernel]

Look at RL-15 and N540. With a 180 gr bullet, I think those would both give top velocities with a non-compressed load.

 

[The Grand Baboon]

Thanks

 

[sage5907]

I think you should consider a 165 grain bullet. Just think, you are shooting a 150 grain bullet at about 2750 fps, a 165 will travel at about 2650 fps, and a 180 at about 2500 fps. BW

 

[gamestalker]

Loading and shooting compressed charges that are published and SAAMI tested is absolutely OK. I load a lot of compressed charges using slow burning powders without any pressure issues.

I hope you are working with published data? The reason I'm asking is because as you go up in bullet weight, the powder charge decreases as published. And unless the published data indicates it is a compressed charge as per application, you shoudln't be encountering compressed charges. Take another look at the data for that powder and the 150 gr. bullet, and the 180 gr. bullet, the charge is going to be significantly reduced for the 180 gr. bullet.

 

[Michigan Trigger]

I have a Tikka T3 lite chambered in .308; my current load is 150gr nosler ballistic tip loaded with 46.0gr varget. (I will use the following example with varget powder)

LEE's Modern Reloading, second edition lists the following

the MAXIMUM overall length for the .308 is 2.810" for any bullet according to the diagram.

150gr bullet loaded with varget has a MINIMUM overall length of 2.800" for jacketed bullet w/ a max charge of 47.0gr compressed (pressure of 59,973 psi at 2,937 feet per second)

180gr bullet loaded with varget ALSO has a MINIMUM overall length of 2.800" for jacketed bullet w/ a max charge of 45.0gr (pressure of 59,138 psi at 2,661 feet per second)

The 180gr bullet is slightly longer than the 150gr, so the 180gr bullet will occupy more space in the case (both bullets must be seated between 2.800" to 2.810.") The pressures of both loads are approximately the same, even though the charge is less with the 180gr. However, the 180gr bullet has more mass (even though the pressure is about the same), so the 180gr bullet will have less velocity.

The overall length for either bullet is the same, so either cartridge loading will fit your magazine (2.800min to 2.810" max)

Hope this example has helped you. I suggest you check out a couple of reloading manuals to concoct what works for you. Different powders can have different MINIMUM overalls, but the cartridge cannot be longer than 2.810"

 

[USSR]

LEE's Modern Reloading, second edition lists the following

the MAXIMUM overall length for the .308 is 2.810" for any bullet according to the diagram.

The maximum OAL for the .308 is entirely dependant upon each individual rifle's magazine length and/or throat location, and is not necessarily restricted to an arbitrary 2.810" length. In the case of the OP, the Remington Model 700's in .308 are notorious for their long throats, and in all likelyhood he will be able to seat the bullets out farther, with the OAL being limited by magazine length.

Don

 

[IDriveB5]

zreed042, I did not have much success with the NBT 180 in my rifle.
I think it would have done much better if I set it out somewhere around 2.900", but I can only fit out to 2.875" in the AICS magazine.

Trying the NBT 168 next. I won't have to seat it any deeper than the SMK175 load that my rifle loves and still be able to fit in the mag.

Try and stick with Varget, it has done extremely well for me with the SMK 175 and has very little variation over the temperature extremes.

 

[Jasper1573]

What powders do I have available that would take up less volume (so I could seat the bullet at least somewhat deeper) and give me a velocity decent enough for hunting?

What velocity do you consider sufficient for hunting? Are you shooting out to 100 yds or 300 yds and beyond. If you load a 180 grn bullet to a velocity of 2400 to 2500 fps, you still have over 1000 ft-lbs of energy at 500 yds. A bullet of that weight doesn't have to travel extremely fast to still have plenty of killing power, depending on what you are trying to kill.

I shoot a Rem 700 5r with 20 inch barrel. 43 grains of RL-15 or 41 grains of AA 2520 will get you to those velocities and be very accurate as well. As far as COAL, I find my Remy likes 2.805 but also does well with 2.800. I have loaded them longer out to 2.810 but found my accuracy began to decrease.

 

[Coltdriver]

Don't know what your twist is. I went with the Sierra round nose in 180 grain for my CZ. The round nose is a bit shorter than the slightly slicker pointy bullets.

It turned out to be the bullet my rifle was made for as it shoots excellent groups. I use Varget and while the loads are not compressed there is not much room left in the case.

 

[Michigan Trigger]

The maximum OAL for the .308 is entirely dependant upon each individual rifle's magazine length and/or throat location, and is not necessarily restricted to an arbitrary 2.810" length. In the case of the OP, the Remington Model 700's in .308 are notorious for their long throats, and in all likelyhood he will be able to seat the bullets out farther, with the OAL being limited by magazine length.

Very true Don...the magazine is almost always the limiting factor with max length. Seating them out farther is fine, pressure will be a little less (as long as the powder charge remains the same.) I suppose one would have to experiment with several test set of rounds at perhaps 0.010 increases. You definitely want to ensure its not too long to feed reliably from the magazine into the bore. You might find a real sweet spot that your rifle punches clover-leafs by experimenting with different overall lengths. Reloading sure is fun like this...thats why i love doing it. It's like you occasionally discover your firearms likes and dislikes...its fun to tinker with different load parameters

 

[The Grand Baboon]

Well here's the situation so far. I'm using 42.5 grains of RL-15 and loading up three rounds every .05" from 2.80" to 3.00" (2.80", .85", etc.) to play around with length. I used the "magic marker" method out of the Nosler reloading guide to determine the OAL. I don't know if I did it wrong (I did it a couple times) but I was ending up with about 3.00" OAL. Given the long length of the 180gr NBT the entire neck of the Winchester 308. brass is in contact with the bullet at 3.00". Is 3.00" way too long?

 

[Jasper1573]

I believe the rule of thumb I have read on THR is 1/3 of your bullet (not counting the boat tail) should be in the brass. Question is, will your bullet stay firmly seated in your brass if the OAL is 3 inches. I have never tried to load out that far, so I am unsure.

 

[USSR]

Is 3.00" way too long?

It's too long to fit in your magazine, isn't it? If the bullet has to be seated out to an OAL of 3.00" to contact the lands, then find out how far you can seat the bullet out and still have it feed from your magazine, and that would be the OAL to seat your bullets to.

Don

 

[The Grand Baboon]

It's too long to fit in your magazine, isn't it? If the bullet has to be seated out to an OAL of 3.00" to contact the lands, then find out how far you can seat the bullet out and still have it feed from your magazine, and that would be the OAL to seat your bullets to.

Yes, it is much too long. If I seat the bullets deep enough to feed, I can hear a barley audible "crunch" noise when I seat the bullet. I can still shake the cartridge and hear powder rattling around, so I don't know if it's just the bullet pushing the powder out of the way.

 

[Michigan Trigger]

its the powder compressing...i normally load w/ varget w/ the 150gr loads. I normally load at 46.0gr; but when i ran the test batch to the max charge of 47.0gr, i would hear the powder crunch because it's a compressed load. This is fine if you are expecting to be a compressed load...probably not okay if it's not supposed to be

 

[USSR]

Yes, it is much too long. If I seat the bullets deep enough to feed, I can hear a barley audible "crunch" noise when I seat the bullet. I can still shake the cartridge and hear powder rattling around, so I don't know if it's just the bullet pushing the powder out of the way.

Don't worry about the crunch, just load them to fit your mag length. It will probably be slightly less than 2.850".

Don

 

[Slamfire]

A shooting bud of mine gave me a 1000 yard target load recommendation of 185 Bergers and 47.0 grains IMR 4350.

I had 190 SMK's. Forty seven grains IMR 4350 completely fills the case, in some thick cases, it over flows. I would crunch those bullets down in that powder column and I would see the bullet rising back as the powder pushed back.

The OAL's were all irregular.

This load will blow primers in hot weather so don't duplicate it.

I would not recommend going over a 175 grain bullet in the 308 as you really start losing velocity in the 308.

But if you are unhappy with 150's, try them and see what happens.

 

[The Grand Baboon]

Well, out of all the lengths I tried (from 2.80-3.00" at .05" increments) 3.00" preformed the absolute best at 100 yards.


The other sizes had groups ranging from a golf ball (2.85"...still not short enough to fit in the mag) to the size of a grapefruit (all lengths other than 2.85" and 3.00"). The only load out of all that would fit the mag (2.8") did horribly.

 

[USSR]

Looks like you single load them, zreed042.

Don

 

[Strongbad]

Looks like you single load them, zreed042.

Don

That, and they probably shoot so well because he was close to the lands where he SHOULD be.

FWIW I've had excellent results with Varget and 165 gr. Nosler BT's in a DPMS LR-308, and AA2230 & Reloader 10x have both performed very well with the same 165 BT's in my 308 bolt gun.