• Watch Out for Scammers!

    We've now added a color code for all accounts. Orange accounts are new members, Blue are full members, and Green are Supporters. If you get a message about a sale from an orange account, make sure you pay attention before sending any money!

  • The site has been updated!

    If you notice any issues, please let us know below!

    VIEW THREAD

Range Report 338 lm going sub sonic before 1k??

jsm.usmc

Sergeant
Full Member
Minuteman
Nov 30, 2008
126
0
38
Clifton Hill, Missouri
Shot out to 1000yd today, my three shots were one the target long ways. Looked as if you traced around the bullet long ways and cut it out with a laser. I will get a picture. I don't have a chronograph yet. My load is 87.8gr. retumbo, 300smk. We then moved up to 800yds and it punches holes like normal. Is it just to light of load?
 
Re: 338 lm going sub sonic before 1k??

What is the twist rate on your rifle? Doubt it very much if it goes subsonic before 1K.
 
Re: 338 lm going sub sonic before 1k??

What is your elevation to 800?
 
Re: 338 lm going sub sonic before 1k??

87.8 is on the light side for a 300grain... I was up in the 92-94 grains on a 26" barrel 338LM. However, I highly doubt it was nearing transsonic range at 1000 yards. Even if it did, I would be surprised if the dynamic stability didn't survive the transition well. What is your twist rate?
 
Re: 338 lm going sub sonic before 1k??

Been plugging some numbers with your info (I like geeking out on this stuff)...

Just guessing at atmospheric conditions in your neck of the woods, I put your muzzle velocity at around 2575fps, and around 1740 fps @ 800 yards, so velocity wise you are nowhere near trans sonic.

That MV should put your stability factor in the 2.3-2.4 range, depending which method you use, which is plenty.

So by the numbers, no red flags.
 
Re: 338 lm going sub sonic before 1k??

My 300SMK runs about 2770 fps. At 800 yards, it takes about 5.1 mil. My take is your velocity is a bit slow.
 
Re: 338 lm going sub sonic before 1k??

Please post pictures, this would be interesting to see. I have seen several 6mm bullets keyhole at that range usually due to twist rate not velocity. However they where not laser cut like you describe.
 
Re: 338 lm going sub sonic before 1k??

I'd almost suggest that the SMKs were out of spec, i.e. out of balance... maybe a bad batch?? Can you try some 300 grain Lapua Scenars instead?
 
Re: 338 lm going sub sonic before 1k??

Have you checked the rifle or slugged the barrel? I know more than one person that has had horrible results with the Savage 110ba. How are the groups at 100,200,300,400,etc?
 
Re: 338 lm going sub sonic before 1k??

IMG_0215.jpg

This is the 3 shot group
IMG_0216.jpg

IMG_0217.jpg

IMG_0218.jpg

There are the individual shots.
IMG_0219.jpg

This was a 308 at 1000 it did same thing basically.
 
Re: 338 lm going sub sonic before 1k??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: flounderv2</div><div class="ubbcode-body">Have you checked the rifle or slugged the barrel? I know more than one person that has had horrible results with the Savage 110ba. How are the groups at 100,200,300,400,etc?

</div></div>I haven't checked anything. My groups everywhere else were great. At 800 i put 2 out of 3 inside a 4" diamond. At 300 i've shot a .882" 5 shot group.
 
Re: 338 lm going sub sonic before 1k??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cali_tz</div><div class="ubbcode-body">I'd almost suggest that the SMKs were out of spec, i.e. out of balance... maybe a bad batch?? Can you try some 300 grain Lapua Scenars instead? </div></div>
If the bullets were bad, would they group at 800? Or closer?
 
Re: 338 lm going sub sonic before 1k??

300grn smk needs a 1/10 at least.
 
Re: 338 lm going sub sonic before 1k??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lazy21</div><div class="ubbcode-body">300grn smk needs a 1/10 at least. </div></div>

It's a 9tw from Savage.


I doubt that it's a twist rate or MV issue. Is there the potential of having the bullet falling short and you skipped it into the target? Making you think you were getting on target but in reality it wasn't happening the way you expected?

Is there a hill in there that the bullets skipped off from potentially?

I know they may sound like very strange questions, however I've seen both happen already to a number of very good shooters at a match.
 
Re: 338 lm going sub sonic before 1k??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bohem</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lazy21</div><div class="ubbcode-body">300grn smk needs a 1/10 at least. </div></div>

It's a 9tw from Savage.


I doubt that it's a twist rate or MV issue. Is there the potential of having the bullet falling short and you skipped it into the target? Making you think you were getting on target but in reality it wasn't happening the way you expected?

Is there a hill in there that the bullets skipped off from potentially?

I know they may sound like very strange questions, however I've seen both happen already to a number of very good shooters at a match. </div></div>

This could be a possibility. Next time i go out to shoot, i will put more elevation in it to verify.
 
Re: 338 lm going sub sonic before 1k??

It can only be one of two things. Like Bohem said, you might be skipping your bullets into the target or Savage screwed up on the twist rate of your rifle and the bullets are losing stability. I think those are pretty much the only two options as to what could be going on.
 
Re: 338 lm going sub sonic before 1k??

I am thinking skipping too, i doubt it would be the twist rate if it was fine at 800 the difference between 800 and 1000 is not all that much for a .338 lapua. (Maybe around 150 fps) What is your dope for 800 and 1000? What kind of backstop was there or was anything behind the target? What is your load's velocity?
 
Re: 338 lm going sub sonic before 1k??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: frankythefly</div><div class="ubbcode-body">I am thinking skipping too, i doubt it would be the twist rate if it was fine at 800 the difference between 800 and 1000 is not all that much for a .338 lapua. (Maybe around 150 fps) What is your dope for 800 and 1000? What kind of backstop was there or was anything behind the target? What is your load's velocity? </div></div>

My elevation for 800 was 22.25. I looked back at my book, i was shooting the same elevation at 1000 as 800. We started at 1000 then moved back. I think the skipping in there might be the answer. Hopefully weather permitting going to try again tomorrow. If it was skipping, thats a pretty good group ha??
 
Re: 338 lm going sub sonic before 1k??

Wait...you have a 308 and 338 both keyholing?
 
Re: 338 lm going sub sonic before 1k??

Skipping has got to be the answer. You shouldn't have 22.25 moa at 1000 if it was on, and not keyholing at 800. You would probably be somewhere around 28-30 moa at 1000. I'm hitting 800 w/ 18.5 moa shooting 250 scenars in a light load, and at 1000 i'm at 26 moa. The muzzle vel. between the two is around 215 fps. Did you notice and dust kicking up before the target? But that's pretty crazy that you had a .308 doing the same thing...
 
Re: 338 lm going sub sonic before 1k??

I was shooting with him, I had the 308.

I didn’t have enough scope to dial in the 1000, so I just dialed up all I could and started holding over. The scope has a BDC and I just started going up with deerkllr spotting. When he saw dirt 3-4 feet low, I just aimed at the top of the target and we didn’t see anything so we thought I was on.

Another thing that makes the skipping seem more and more likely is that while my poa was at the top of the target, the target being 8’, and my moving from the center to the top thinking I was 3-4 foot low, well this should put me on or near the center. My shot was 1-1.5 foot from the top.

We might get to try again today.