PDA

View Full Version : Start load development at SAAMI OAL? (308, 168, 4064)


blockfort
07-15-2016, 12:11 AM
I have new projectiles (168 SMK) for my 308 WIN loads. I'll be using IMR 4064 and will work my way up from Hodgdon's minimum.

But what length should I seat to? If I make them 2.8" OAL, there's about 0.1" jump to the lands. Is that normal and ok?

kcstott
07-15-2016, 4:02 AM
It is normal if you plan to feed your rounds from a mag. be it box or detachable.

Military went to the M24 rifle system which is a long action 700. they did this for two reason, one you can build a rifle in two caliber on one action, two you can now seat your bullets out where the need to be and still feed them from the mag.

Now all that said, I shoot 175 SMK's or Bergers and seat then to saami spec 2.8" and i can punch nice one maybe two hole five shot groups. The vlds like a little jump

blockfort
07-15-2016, 7:40 AM
I plan to single load into my Browning A-Bolt Target, but charge weight and seating depth makes a 2-dimensional matrix (more if you experiment with other variables), and so there's just so many possibilities.

Will the best charge weight still be the best regardless of seating depth, and just get better when the depth is tuned?

OpenSightsOnly
07-15-2016, 8:09 AM
I plan to single load into my Browning A-Bolt Target, but charge weight and seating depth makes a 2-dimensional matrix (more if you experiment with other variables), and so there's just so many possibilities.

Will the best charge weight still be the best regardless of seating depth, and just get better when the depth is tuned?


Buy this or make/fabricate a similar one - http://www.hornady.com/store/OAL-Gauges/

Buy a reloading manual like Sierra, try out their load then play with the seating depth with the Hornady gauge.

Bill Steele
07-15-2016, 9:52 AM
I plan to single load into my Browning A-Bolt Target, but charge weight and seating depth makes a 2-dimensional matrix (more if you experiment with other variables), and so there's just so many possibilities.

Will the best charge weight still be the best regardless of seating depth, and just get better when the depth is tuned?

There was a similar thread on this very subject recently here. Some of the heavy weights (and not so heavy weights) opined and a lot of good data was exchanged. If I were better with the search function, I would just post the link.

Found it (on the front page, pretty easy): http://www.calguns.net/calgunforum/showthread.php?t=1213465

To answer your basic question, I have always found locating a wide node (charge weight) to be the first step, jump is usually one of the latter steps.

blockfort
07-15-2016, 4:41 PM
Buy this or make/fabricate a similar one - http://www.hornady.com/store/OAL-Gauges/

Buy a reloading manual like Sierra, try out their load then play with the seating depth with the Hornady gauge.

I have a similar tool, but usually rely on a loose neck case and the actual bullet I'm loading. Regardless, I know my chamber dimensions now, but am trying to figure out what the best process is to find both charge weight and seating depth.

blockfort
07-15-2016, 4:53 PM
There was a similar thread on this very subject recently here. Some of the heavy weights (and not so heavy weights) opined and a lot of good data was exchanged. If I were better with the search function, I would just post the link.

Found it (on the front page, pretty easy): http://www.calguns.net/calgunforum/showthread.php?t=1213465

To answer your basic question, I have always found locating a wide node (charge weight) to be the first step, jump is usually one of the latter steps.

Reading this now, thanks.

OpenSightsOnly
07-15-2016, 5:06 PM
41.5 or 42 grains of IMR 4064 with a 168 SMK bullet. That is the accuracy load based on M852 match ammo. FGMM is similar to M852.

42 grains of IMR 4064 with 175 SMK is Mk.316 ammo.

If you have a chrono and a reloading manual, even better. This is 308 Win, don't sweat it.

1badlvn
07-15-2016, 5:24 PM
41.5 or 42 grains of IMR 4064 with a 168 SMK bullet. That is the accuracy load based on M852 match ammo. FGMM is similar to M852.

42 grains of IMR 4064 with 175 SMK is Mk.316 ammo.

If you have a chrono and a reloading manual, even better. This is 308 Win, don't sweat it.
I agree with this 42gr of 4046 and 175gr smk loaded to 2.800 in FC brass gets me 2650fps out of my 24inch 5r and makes me jizz my pants up to 400 yards with the groupings. Gotta keep a spare pair just in case. I experimented loading to the lands at 1.915 and found no gain in accuracy, Just a funky looking round.

Sent from my SM-N910V using Tapatalk

blockfort
07-15-2016, 7:31 PM
41.5 or 42 grains of IMR 4064 with a 168 SMK bullet. That is the accuracy load based on M852 match ammo. FGMM is similar to M852.

42 grains of IMR 4064 with 175 SMK is Mk.316 ammo.

If you have a chrono and a reloading manual, even better. This is 308 Win, don't sweat it.

I pulled one two days ago (FGMM 168 smk) and measured 43.3gr, could they have changed the recipe?

OpenSightsOnly
07-15-2016, 9:16 PM
Were you able to confirm that the powder is IMR 4064?

They can change the powder charge in order to meet the velocity of 2650. For FGMM 175, I think its 2550? They work with different powder lots so I'm sure that they are blending the different lots.

Why don't you shoot/chrono the FGMM 168. If your rifle likes or doesn't like the load, then you have a starting point either way.

JMP
07-15-2016, 10:29 PM
I have new projectiles (168 SMK) for my 308 WIN loads. I'll be using IMR 4064 and will work my way up from Hodgdon's minimum.

But what length should I seat to? If I make them 2.8" OAL, there's about 0.1" jump to the lands. Is that normal and ok?

The length depends on your rifle's chamber. 0.1" is fine if that is what the rifle likes to shoot. I use 168 SMKs, and I load them to 2.800" with 44.4gr of 4064 with CCI LRP, and that doesn't miss (well, a little bit now that my barrel is worn out). But, I have a tight chamber without a lot of freebore. You should load them to the lands and work backwards. If it is something like a Remington 700 factory barrel, you will probably best load them longer since the chamber is so big. If you are limited by magazine size, then start there; otherwise, start at the lands and work backwards.

castgold
07-15-2016, 10:43 PM
Are you loading into a magazine that can accept a longer COAL? I try for 0.05" off the lands, or even closer depending on the rifle.

blockfort
07-15-2016, 11:13 PM
Are you loading into a magazine that can accept a longer COAL? I try for 0.05" off the lands, or even closer depending on the rifle.

As I stated at the beginning of the thread, I am single loading through the ejection port. But if I load to be right off the lands, there's less than a tenth of an inch of bullet in the neck. If I load to 2.800 OAL for load testing, there's a tenth of an inch jump. I'm trying to figure out which of those scenarios I should use to test my charge weights, before moving to seating depth optimization.

smoothy8500
07-16-2016, 6:51 AM
As I stated at the beginning of the thread, I am single loading through the ejection port. But if I load to be right off the lands, there's less than a tenth of an inch of bullet in the neck. If I load to 2.800 OAL for load testing, there's a tenth of an inch jump. I'm trying to figure out which of those scenarios I should use to test my charge weights, before moving to seating depth optimization.

My Rem 700 had a long throat too. Just load to 2.810" and call it good. When you rebarrel your rifle with a decent throat length then you can worry about depth.

Metal God
07-16-2016, 8:24 AM
The 168gr Fed GMM is in fact loaded with 43.3 to 43.5gr IMR 4064 . Not going into how I know this , way to long and complex .

As for seating depth . The first thing you need to do with any bullet that you may be able to load at or in the lands is to figure out at what COAL length the bullet touches the lands . There are multiple ways of doing this from using the Hornady gauge to just using a fired case and very lightly crimping the neck to just hold the bullet . You then seat the bullet very long in the case . You now chamber that round and when the bullet hit the lands it's pushed back into the case . Carefully extract the round and measure . That method does take a bit of getting used to and if done wrong can result in very inconsistent COAL .

Generally if you plan to adjust seating depth later to fine tune your load . You will want to start with the cartridge as long as you can have and still function in the firearm in the way you intend . Meaning if you plan to load from the mag . Then the COAL can not exceed the ability to fit in the mag . The point of loading long or at the lands to start with is if the load you later want to adjust seating depth with is at max pressure . You can only adjust seating depth away from the lands which should be safe to do with a max pressure load . If you do it the other way around and start way off the lands and you end up with a max pressure load . Adjusting the seating depth closer and closer to the lands can easily send your pressures way over max .

If you are new to this type of fine tune loading I recommend finding your MAX COAL then back off the lands .020 and start loading there . Once you have more experience and understanding with this type of loading . You can start using some of the more advanced methods to fine tune the load

blockfort
07-16-2016, 8:30 AM
The 168gr Fed GMM is in fact loaded with 43.3 to 43.5gr IMR 4064 . Not going into how I know this , way to long and complex .

Everyone seems to say it is 4064, and I personally measured 43.3/43.4 grains, though I have seen other numbers in places.

JMP
07-16-2016, 4:05 PM
Everyone seems to say it is 4064, and I personally measured 43.3/43.4 grains, though I have seen other numbers in places.

That's what I have heard too. Really, all you need to know is Varget or 4064 for 168s. I'd not touch anything else; most people prefer Varget. I started with Varget, but I moved to 4064 when Varget was super hard to find, and I actually got better results (same accuracy, but a few more FPS).

blockfort
07-16-2016, 4:37 PM
That's what I have heard too. Really, all you need to know is Varget or 4064 for 168s. I'd not touch anything else; most people prefer Varget. I started with Varget, but I moved to 4064 when Varget was super hard to find, and I actually got better results (same accuracy, but a few more FPS).
I have a ton of h4895, what's that good for? I have lots of 155smk, and a small box of 190's to test

Sent from my SM-G920V using Tapatalk

LynnJr
07-16-2016, 5:14 PM
You can use H4895 or RE15 and get great results with the 168's.
On the seating depth if you are working up your load go as long as you can go.
After you get a powder charge that works all you have to do is adjust your seating depth in one direction only.
Powder has the biggest influence on your guns accuracy and seating depth is the second most important part of accuracy.

Victor Cachat
07-16-2016, 6:08 PM
Every one of my chambers but one is more than 0.1" over SAAMI spec. and magazine length is as far as I can go, unless I want to feed the rounds by hand.

I would concentrate on the powder load first.

And my .308s all like ~41gr of 4064

blockfort
07-21-2016, 6:16 PM
Sort of an update here (http://www.calguns.net/calgunforum/showthread.php?p=18506373#post18506373).