abnormal drop

gunship · May 27, 2015

I have a .308 Remington 700 SPS Varmint, 26" 1:12 twist barrel, in a B&C medalist stock, with a vortex PST on top.
I was shooting some 175 gr Berger OTMs and decided to move out to 230 yards(the farthest on my property). The drop from my 100 yd zero was 11 inches. The load was 44 gr of BLC2 under a 175 gr OTM. I sadly do not have access to a chronograph but putting everything into the Vortex ballistic calculator says it would be 2032 fps. That seems really low. Is the drop normal? Is the estimated velocity close?(Berger gives about 2500 from a 24 inch barrel) I tried searching for some answers before posting but didn't find much. I hope I got all the details.

notaglockfanboy · May 27, 2015

Although I have not used BLC2 in the .308 that does seem slow to me. I suppose that much drop could be expected. Hang tight, the calvary will be along shortly to help you with this issue. I am hanging around as well, because I am curious too.

jwrowland77 · May 27, 2015

When using the apps (I use Ballistic AE), you adjust your scope for what the app says it should be, shoot 3 rounds or so, then plug that difference in the app to true the data.

What you have seems really slow.

243winxb · May 27, 2015

Bullet drop depends a lot on how high the scope is above the bore. Here is some factory ammo info. http://www.federalpremium.com/products/details/rifle.aspx?id=151 See average range and long range. If your sighted in at 100yds, the 308 will drop till it gets to 200. A 220 swifts bullet will still be going up with a scope 1.5" above the bore.

gunship · May 27, 2015

Well I did some things I should have caught earlier.
1. I ranged with the scope instead of pacing it and it came out to 250 yds.
2. i remeasured my scope height and took a little more time.

Of course drop stayed the same but the calculator now gives 2338 fps. To me that still seems slow but at least it isn't as slow. I hope I didn't waste anybodies time but if there is more input I would love to hear it

joed · May 27, 2015

I've never used BLC2 so can't comment on that. What I will say is not every powder will give velocities as advertised. Varget is one that I can not get to match a load manual. For some reason I need 2 gr more to hit advertised speed. May be just the batch I have, I don't know.

This is why I have a chronograph. I do like what jwrowland77 suggested, that should give a really good estimate of velocity.

osprey176 · May 27, 2015

Accurate measurement will give usable data. I would say bite the bullet and pick up a chronograph. Chronys are around $100,and while maybe not the best,will give you good information instead of using the Swag method.

jmr40 · May 27, 2015

You really need a chronograph. I've seen as much as 130 fps difference with ammo from the same box fired from 2 different rifles with the same barrel length. You may just have one of those rifles that shoots everything slower than it should. It happens.

You are quite a bit below a max load too. I'd add more powder, especially if a chronograph showed I was well below the speeds I should be getting.

gunship · May 27, 2015

I went to the max load but the accuracy just wasn't there. A chronograph would be great but at the moment I just qualified for Warrant officer Candidate school and will be going to basic training soon and will not get much use out of it before I go.

abnormal drop

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