Didn't want to hijack any other threads but looking for advice from guys like Mystic and Obtunded with alot of longer range experience using reloaded ammunition. I have an Accuracy International AE MK II in .308 Win and currently only shoot factory Match ammunition, Fed GMM 168 grain. I have shot out to 1000with the rifle with okay results but obviously with not reloading I am limiting myself at the time with the 168 grain bullet. Any recommendations with respect to bullet, loads etc for a 20 inch barrel with a 1 in 12" rate of twist. I know guys are using much longer barrels but would something like a 155 gr Scenar or Berger 155.5 fullbore work in short barrel or something along the lines of a 175 gr Smk or Berger 175 VLD etc. I realize I would have to work up the loads in this particular rifle and find what works best but was just looking for some advice with guys who already may have been down this road. Thanks.
Shooting to 1000m with 20 inch barrel.
- Thread starter EC
- Start date
I currency run a 21 inch barrel and am using 175 gr bergers. I haw also used the 175 smk, both with awesome results out to 1000 and beyond. Stuck with the bergers originally to be different, but just like the final product a little better then the smk's. Reality is the both shoot consistently. Also used a 175 gr load when I was shooting with my ltr. Again shot very well. The weight helps and had no issues with stabilizing the 175's. I have not gone the 155 route but know guys like blackcloud on the board who have, again with good results. Blackcloud also had an aw setup so e might be able to throw some load data your way to get you started.
- Location
- calgary alberta
The 168s do not seem to transition from super sonic to sub sonic well. The 155 Scenars or 175 SMKs seem to work better in this regard. If factory ammo is the plan, the 178 Amax loaded in the TAP ammo has shown excellent promise.
Several of us here are running 21" barrels as C4 mentioned and have absolutely no problem getting beyond 1000 yards of accuracy.
I have stepped up to the 190 gr SMKs using N550 powder and it is working extremely well out to 1400 yards.
IIRC C4 is using Varget with the 175s and we know it works well for him.
Several of us here are running 21" barrels as C4 mentioned and have absolutely no problem getting beyond 1000 yards of accuracy.
I have stepped up to the 190 gr SMKs using N550 powder and it is working extremely well out to 1400 yards.
IIRC C4 is using Varget with the 175s and we know it works well for him.
My experience shooting to 1000 with a short barrel is the same as what others are saying. The performance of a 168 grain bullet past 800 yards is not the best irregardless of the barrel length. 155's or 175's will perform much better in my experience at 1000 using a 20 inch barrel. I used Hornady and Sierra match kings.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Many bullets will travel and go subsonic just fine. The 168gr MK is a glaring exception.
Most of the bullets listed and the Amax and Hrn BTHP will make the trip nicely.
The 155gr Amax was a favorite for inexpensive LR plinking that handled extreme distances no problem. Furthest I shot out of 308 was 1450yds (ran out of real estate). I have shot this bullet beyond 1 mile in a 300Wby
the other 155 and 155.5gr bullets should also make the trip to 1000yds without much fuss. These bullets are used all the time to 1200yds in long barreled 308's so 1000yds would be similar velocity.
Load them and shoot them. That is the best way to know for sure.
Jerry
Most of the bullets listed and the Amax and Hrn BTHP will make the trip nicely.
The 155gr Amax was a favorite for inexpensive LR plinking that handled extreme distances no problem. Furthest I shot out of 308 was 1450yds (ran out of real estate). I have shot this bullet beyond 1 mile in a 300Wby
the other 155 and 155.5gr bullets should also make the trip to 1000yds without much fuss. These bullets are used all the time to 1200yds in long barreled 308's so 1000yds would be similar velocity.
Load them and shoot them. That is the best way to know for sure.
Jerry
The 168 SMK has inherent long range instabilities outside of the trans-sonic passage issue, according to Litz IIRC. With a 20" barrel, you lose some velocity and if you have a spotter along side you, I hear that they may have some issues with following the bullet trace and impact due to the increased muzzle blast. My 1000 yd 308 has a 26" barrel in 1x11.25 and it shoots the 155 Lapua, the 210 Berger and this year the 190 Berger. My tac 308 in 1x11.25 struggles to shoot 175 SMK to 900m, but the sweet spot is 700m. This is Homestead at 4800' ASL.
All the bullets you listed will work. I'd recommend that you pick up a 1000 rd case of factory in Lapua 155 or Norma 190 if you're serious about long range shooting without reloading (175 Fed Match if you're just trying out some long range, but the brass is not the best for accuracy reloads). The empty brass gives you a solid starting point when you do go to reload (and the sticker shock gives you impetus to buy some reloading gear ... and surprise - the Lapua or Norma isn't that much more than Fed match). The 1x12 will work across most altitudes you'll encounter, for just about all bullet weights in 308.
Bill
All the bullets you listed will work. I'd recommend that you pick up a 1000 rd case of factory in Lapua 155 or Norma 190 if you're serious about long range shooting without reloading (175 Fed Match if you're just trying out some long range, but the brass is not the best for accuracy reloads). The empty brass gives you a solid starting point when you do go to reload (and the sticker shock gives you impetus to buy some reloading gear ... and surprise - the Lapua or Norma isn't that much more than Fed match). The 1x12 will work across most altitudes you'll encounter, for just about all bullet weights in 308.
Bill
- Location
- Somewhere on the Hudson Bay Coast
I know that light bullets seem to be the preferred choice of many here, but a .308 with a 20" barrel gives up less velocity from a heavy bullet than it does from a light one. A 155 can hit 3000 fps from a 30" barrel, but from a 20" I would anticipate something more like 2700. Conversely a 200 or a 210 gr bullet can get 2600 from the long barrel and 2500 from a 20", and at 2500 a 210 remains supersonic to about 1200. The 155 at 2700 goes subsonic at about 930 yards. If the 155s remain stable once subsonic all is good, but the heavier bullets have an advantage.
Actually, if factory ammo is what you want to use, there are a number of excellent choices in .308 Paul Reibin of Range Sports Unlimites carries a variety of pretty esoteric 308 match ammo.
You might be intereted to know that in many international iron sight competitions, where 308 ammo is used exclusively, the ammunition is actually issued to the shooters so everyone uses the same stuff.
I personally had excellent results with 178 Amax bullets in a 24" barrel at 1000 yards, but there are sooo many good choices. A 20" barrel is not a handicap for 1000 yard shooting. Also, I believe it is onl;y the Sierra 168 that has instability isses. the 168 hornady match bullets are fine and i have used these in a 30-06 at 1000 with good results.
You might be intereted to know that in many international iron sight competitions, where 308 ammo is used exclusively, the ammunition is actually issued to the shooters so everyone uses the same stuff.
I personally had excellent results with 178 Amax bullets in a 24" barrel at 1000 yards, but there are sooo many good choices. A 20" barrel is not a handicap for 1000 yard shooting. Also, I believe it is onl;y the Sierra 168 that has instability isses. the 168 hornady match bullets are fine and i have used these in a 30-06 at 1000 with good results.
- Location
- calgary alberta
Something we proved to a lot of doubters by going with a short barrel is that you don't have to sacrifice distance just because you don't have a 24+" bbl. On the contray, you can actually push your bullets a lot more because the barrel length and the lack of pressure as a result. Now that I've comfortably run the 175gr SMK out to 1550yds and gathered bullet drop data from 1000yrs, my next project will be to creat a load using the 155gr scenars if my twist will allow it. I was very impressed with how my gun handled the 175gr bullets but I like to play so a new challenge is in the works.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
When you use top of the line components with tight tolerances, and your load development is done correctly in a safe fashion, the results can be astounding. You can only go so far on a shoe string budget but when built from the ground up, you can achieve what others consider unachieveable and with consistency.
The Accuracy International is a solid chassis built for the above average loader. Sure you could run middle of the road forever but why if you can improve on the results.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Any pressure data?
you know I don't make my comments lightly and I have been around enough high end gear to know what I 'm talking about.
Just because there are no 'pressure signs' on the case, doesn't mean there isn't any pressure IN the case.
Show me a pressure trace of your rifle illustrating how you can change the laws of physics with quality components (which we all have access to and many of us use) and I am sure it will make your company very wealthy.
I know the US ARMY is looking for such tech right now and are spending HUGE $$$
Some of it will start to trickle down to use in 2011 but I really doubt these components are in Canada yet.
And if the magic potion is a Viht powder, we have all been there and had the Kool Aid.
Jerry
you know I don't make my comments lightly and I have been around enough high end gear to know what I 'm talking about.
Just because there are no 'pressure signs' on the case, doesn't mean there isn't any pressure IN the case.
Show me a pressure trace of your rifle illustrating how you can change the laws of physics with quality components (which we all have access to and many of us use) and I am sure it will make your company very wealthy.
I know the US ARMY is looking for such tech right now and are spending HUGE $$$
Some of it will start to trickle down to use in 2011 but I really doubt these components are in Canada yet.
And if the magic potion is a Viht powder, we have all been there and had the Kool Aid.
Jerry
I think everyone does very similar load development so this isn't rocket science but if you can run Lapua brass, 46 3/4gr of varget powder, 210M primers and SMK 175 bullets loaded to Accuracy International mag length and reuse your brass as many times as I have and continue to, you're just as much a magician as I am. A while back I took the time to shoot a 5 shot group at 100yds, which doesn't proove much as far as I'm concerned, which measured outside to outside .483. The amazing thing about this load was that every gun that was made from the same components as mine, and there were a bunch, could run the exact same load and perform equally as good.
If I'm bending the laws of physics, maybe the calculations of the laws were off a little because I've just given up the secret.
As for pressure, my primers don't fall out of the pockets and I haven't lost a single piece of brass to seperation or failure. Also, I haven't trimmed any of the brass to date either. Theres a lot to be said for repeatable manufacturing of firearms, I think. I like to keep things simply and not worry about much till I start seeing signs of failure. At that point, it's worth looking into. THere's no point putting that kind of thought into the universe. That's how sh!t happens.
If I'm bending the laws of physics, maybe the calculations of the laws were off a little because I've just given up the secret.
As for pressure, my primers don't fall out of the pockets and I haven't lost a single piece of brass to seperation or failure. Also, I haven't trimmed any of the brass to date either. Theres a lot to be said for repeatable manufacturing of firearms, I think. I like to keep things simply and not worry about much till I start seeing signs of failure. At that point, it's worth looking into. THere's no point putting that kind of thought into the universe. That's how sh!t happens.
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Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Well, your loads aren't insanely hot but you aren't SAAMI either. You might want to run your data through quickload and see what you get.
65000psi is considered magnum pressures.
80,000psi is proof pressure loads.
Where are you?
Be careful about waiting for failure. That first one could be pretty spectacular.
Be safe....
Jerry
That's a pressure trace:
Pressure peaks within 1/3 the way down the barrel and that peak looks the same in a 22" barrel as it does in a 28" barrel with similarly spec'd custom barrels. The bullet is nowhere near the end of the barrel at the peak, so the final length makes absolutely no difference. It does affect the pressure at the muzzle though... which is higher for the shorter barrel.
Going with a tighter barrel actually INCREASES peak pressure sightly. But, it also gives you a more complete burn, which is why you don't lose as many fps. even with the shorter barrel. I have a 0.3075/0.298 Bartlein blank that's destined to be an 18" barrel for that very reason...
That being said, 47.5 gr. of Varget with a 175 SMK should put peak pressure at around 68-69K psi in any of the barrels I've tested (Bartlein and Broughton > 0.308/0.299, Kreiger and Rock > .308/300 ). That's based on extending the trend line of the data I have, which is only up to 62K~ish with around 46 gr.
Pressure peaks within 1/3 the way down the barrel and that peak looks the same in a 22" barrel as it does in a 28" barrel with similarly spec'd custom barrels. The bullet is nowhere near the end of the barrel at the peak, so the final length makes absolutely no difference. It does affect the pressure at the muzzle though... which is higher for the shorter barrel.
Going with a tighter barrel actually INCREASES peak pressure sightly. But, it also gives you a more complete burn, which is why you don't lose as many fps. even with the shorter barrel. I have a 0.3075/0.298 Bartlein blank that's destined to be an 18" barrel for that very reason...
That being said, 47.5 gr. of Varget with a 175 SMK should put peak pressure at around 68-69K psi in any of the barrels I've tested (Bartlein and Broughton > 0.308/0.299, Kreiger and Rock > .308/300 ). That's based on extending the trend line of the data I have, which is only up to 62K~ish with around 46 gr.
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
Great info.
Using some extrapolation data, I was in the high 69K/70K as well. This cannot include any increase due to a tight bore and variations in lot to lot or the effects of primers. Only direct testing will give you the best data.
So nothing is going to "blow up" per se but the pressures will quickly start to stress the steel in the action and barrel.
As White Lab discusses, in proof pressure testing, steel rapidly breaks down once a threshold pressure has been reached. Below this, the steel can survive 10,000's if not 100,000's of firings.
Go above and suddenly, the steel can show fatigue in several thousand rds.
What is the threashold in a specific action? That is for far more skilled engineers to say but since all of these actions are made from the same class of steel, their lifespan should fall in the same ballpark.
As I said, custom actions can be made to wonderfully tight tolerances which can hide normal pressure signs BUT the pressure is still there.
I have proof pressure cases used by Rem to test their actions and there is ZERO outward signs of pressure. Not even flattened primers. I was told that the action was opened with only light finger pressure.
This proof load was at least 80,000 PSI
Until someone can show me proper pressure trace info which changes the load data produced by all the reloading component companies, I am going to lean towards the big boys.
Be safe.... There is no free lunch
Jerry
Using some extrapolation data, I was in the high 69K/70K as well. This cannot include any increase due to a tight bore and variations in lot to lot or the effects of primers. Only direct testing will give you the best data.
So nothing is going to "blow up" per se but the pressures will quickly start to stress the steel in the action and barrel.
As White Lab discusses, in proof pressure testing, steel rapidly breaks down once a threshold pressure has been reached. Below this, the steel can survive 10,000's if not 100,000's of firings.
Go above and suddenly, the steel can show fatigue in several thousand rds.
What is the threashold in a specific action? That is for far more skilled engineers to say but since all of these actions are made from the same class of steel, their lifespan should fall in the same ballpark.
As I said, custom actions can be made to wonderfully tight tolerances which can hide normal pressure signs BUT the pressure is still there.
I have proof pressure cases used by Rem to test their actions and there is ZERO outward signs of pressure. Not even flattened primers. I was told that the action was opened with only light finger pressure.
This proof load was at least 80,000 PSI
Until someone can show me proper pressure trace info which changes the load data produced by all the reloading component companies, I am going to lean towards the big boys.
Be safe.... There is no free lunch
Jerry
