Lapua bullet recommendation for IBI 308 prefit barrel

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gunlaker

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Hi,

I'm looking for a Lapua bullet recommendation. Rifle is a 308, 11.25 twist, IBI prefit. Targets not hunting. Range from 200m to 800m. I've been using up my old supply of 168 & 178gr Hornady Amax. I'd ilke to give Lapua bullets a try and was hoping someone had good success in an IBI Prefit barrel. No idea what the chamber is on these, but it has less freebore than the factory Rem 700's I used to shoot.

Thanks,

Chris.
 
Well, depending on your barrel length there are two schools of thought in .308.

You can either lob a heavier higher BC bullet out of a shorter barrel, or you can go for maximum speed with a light bullet in a long barrel. I prefer the latter (155 @ 2950ish).

If your new tube has limited freebore and is on the long side, I’d honestly be looking at the Berger 155.5 instead as its ogive is closer towards the base of the bullet than the Scenars.

That said, we need to know your barrel length and land measurement to start suggesting bullets for you to try.
 
Thanks. The barrel is 24" long.

A 168 a-max touches the rifling @ 2.852" OAL
A 178 a-max touches the rifling @ 2.834" OAL

So both bullets are close to max length when loaded to fit in the MDT ACIX magazine.

I've been loading the 178's at 2.810" OAL.

Chris.
 
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If you are wanting to shoot 155 Scenars, you have to keep the initial bullet velocity higher than 2750 fps in order to stay above the transonic zone at 800 meters. With 24" barrel this should be doable. Your magazine has a binder plate which limits you to 2.87" OAL. The MDT ACIS magazines without binder plates allow for 2.96" OAL. However, you may have to notch out the bottom of the feed ramp to allow the bullet to feed. You will have to experiment. Berger 155.5 was mentioned earlier, it is better in the wind, and also a quality product.
 
gunlaker said:
Thanks. The barrel is 24" long.

A 168 a-max touches the rifling @ 2.852" OAL
A 178 a-max touches the rifling @ 2.834" OAL

So both bullets are close to max length when loaded to fit in the MDT ACIX magazine.

I've been loading the 178's at 2.810" OAL.

Chris.
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Plenty of room. Work up to a near max load of Varget in a Lapua case and seat a 155 out at around 2.880” to see if you can hit some speed (remove mag binder plate as was suggested).

As a refrence, I’m at 2.885” OAL with a Berger 155.5 Fullbore (uncompressed) in a 26” barrel getting 2935 fps which rips out to 1150 yds after which it falls out of the sky.
 
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gunlaker said:
both bullets are close to max length when loaded to fit in the MDT ACIX magazine.
Click to expand...
Does OP need to shoot from the mag? If you are just shooting targets there is no reason to be limited by the magazine. I 3D printed myself some single loading blocks for my AICS chassis and find I use those most of the time. Except for hunting or competition, there is little reason to have ammo fit the magazine.


Terry Perkins said:
If you are wanting to shoot 155 Scenars, you have to keep the initial bullet velocity higher than 2750 fps in order to stay above the transonic zone at 800 meters. With 24" barrel this should be doable.
Click to expand...
My 25" barrel pushes the 155 Scenar to 3050 fps which keeps it supersonic well past 1500 yds.

Interestingly, I also have a load for the 208 AMAX in the same rifle, that leaves the muzzle at only 2480 fps but due to its much higher BC, it is also supersonic past 1500 yds.
 
gunlaker said:
Hi,

I'm looking for a Lapua bullet recommendation. Rifle is a 308, 11.25 twist, IBI prefit. Targets not hunting. Range from 200m to 800m. I've been using up my old supply of 168 & 178gr Hornady Amax. I'd ilke to give Lapua bullets a try and was hoping someone had good success in an IBI Prefit barrel. No idea what the chamber is on these, but it has less freebore than the factory Rem 700's I used to shoot.

Thanks,

Chris.
Click to expand...
I know you said Lapua bullets but if the 178 Amax shoot well, I'd look at the 178 ELDMs. The BC in the newer 175/178 class bullets is much better than the old 175 SMK and I'd wager that you could probably hit 2700 fps in a 24" barrel. I've shot 10s of thousands of 175 RDFs and they've been great in every custom barrel I've tried them in. 43.3gr Varget gave me around 2750fps out of a 26" barrel. That will do you better in the wind than any 155gr class bullet.
 
My 308's are typically 1:10 but I have shot a passle of 1:12's , 1:13.5's and 1:14's over the years .
For an IBI 1:11.5 twist , anything from 155 to 185 will work just fine. But as Terry Perkins stated. You will have to watch your velocity and if you Want to run with your magazine, bullet length.
All in all,a 155 to 168 Seirra Match King, Hornady 155 BTHP, or a Lapua Scenar will work just fine , depending on your requirements.
My current irons rifle in 308 usually gets shot with 155's out to 500 and 175's from 500 to 1,000. It has a Bob Jury 30" , 1:10 barrel however
Cat
 
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