Rifling:Projectile weight question

klink1983

klink1983

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I tried my hand at firing beyond 500 metres this passed weekend. I was touching paper at least, I've never shot that far before. I know I wasn't really reading the wind that well and I made the STUPID mistake of taking off my bipod and shooting supported on my bag after 400m. (5 shot groups each at 200, 3, 4, 5, and 600.) I know most of my issues were user related so don't take this as blaming my equipment aside from not having the best rifle out of 9 shooters.

I am running a Remington 700AACsd in 308, most of you know that has a 20" barrel but faster 1:10 rifling. I didn't have the time to do up any hand loads before the shoot (I'm also a new reloader) so I ended up rocking with Norma BTHP 168gr. I have had some guys tell me to go to 150gr, and others to go heavier. To me, heavier makes more sense on account of the rifling and that it would aid in stability of the heavier projectile which I think could give me a smidge more distance.

Thoughts?

A friend of mine who shoots F class told me if he had my rifle he wouldnt be shooting lighter than 178gr.
 
With a 1:10 twist, you can stabilize up to 200gr bullets. You can't really over-stabilize a bullet, at least not easily. As the twist increases, more energy is taken from propelling the bullet forward and put into spinning it. So shooting an excessively light bullet in a short twist is inefficient, though I don't know how much of a difference it makes.

My .308 has a 1:10 twist, and I've been shooting 168/175/185 grainers.
 
Take a look here at Bergers recommended twists for bullet weights

115 gr Match FB Target .308 115 0.296 N/A 0.942 1:19″ 30421
150 gr Match FB Target .308 150 0.398 N/A 1.172 1:15″ 30407
155 gr Match VLD Target .308 155 0.439 0.225 1.256 1:14″ 30408
155 gr Match Hybrid Target .308 155 0.483 0.247 1.280 1:12″ 30426
155.5 gr Match Fullbore Target .308 155.5 0.464 0.237 1.250 1:13″ 30416
168 gr Match VLD Target .308 168 0.473 0.242 1.265 1:13″ 30410
168 gr Match Hybrid Target .308 168 0.519 0.266 1.296 1:12″ 30425
175 gr Match BT Long Range Target .308 175 0.515 0.264 1.348 1:13″ 30420
175 gr Match VLD Target .308 175 0.498 0.255 1.288 1:13″ 30412
185 gr Match BT Long Range Target .308 185 0.560 0.283 1.353 1:12″ 30418
185 gr Match VLD Target .308 185 0.549 0.281 1.378 1:12″ 30413
185 gr Match Hybrid Target .308 185 0.569 0.291 1.435 1:11″ 30424
200 gr Match Hybrid Target .308 200 0.624 0.320 1.500 1:11″ 30427
210 gr Match BT Long Range Target .308 210 0.626 0.320 1.453 1:11″ 30419
210 gr Match VLD Target .308 210 0.631 0.323 1.459 1:11″ 30415
215 gr Match Hybrid Target .308 215 0.696 0.356 1.564 1:10″

You are thinking in reverse Heavy bullets use faster twist
168gr 12 twist works better than 1/10
manitou
 
If you are using factory ammo, shoot the stuff that groups the best at 200yds and have at it. For the distances you mention, it really doesn't matter. What does is the quality of ammo vs the needs of your barrel. Look for the lowest vertical dispersion and if you have 2 loads that shoot the same accuracy, the flattest group gets the nod.

Good luck..... and really think about handloading.

Jerry
 
Hand loading is the way to go.....I would be trying the 185 match hybrid target or the 168 match hybrid target. That being said, with a 20" barrel I would really push the 168 match hybrid target due to the high BC and reduced weight for increase velocity, with a 20" barrel you are at a disadvantage as far as velocity goes to start with so the lighter bullet will help with keeping the velocities up for when you decide to reach further out.
 
Nothing wrong at all with shooting 168 grain factory match ammo out to mid range (about 600). It's expensive, but that's really the only "bad" thing to be said about that ammo.

If you ever want to shoot beyond 600 metres, there are (much!) better choices of bullet to be had, whether you are using purchased match ammo or are making your own ammo by then. But for 600 and closer, what you were using is great.

*FAR* more important that a specific bullet weight, is whether it is a high quality bullet (the Sierra 168 Matchking used in the Norma 168 Match is a high quality bullet). And with a factory barrel, whether or not your barrel happens to "like" or "dislike" a particular high quality bullet (one of the advantages of match barrels is that they will shoot pretty much any high quality bullet well, and are usually *not* fussy)
 
Mystic Precision said:
If you are using factory ammo, shoot the stuff that groups the best at 200yds and have at it. For the distances you mention, it really doesn't matter. What does is the quality of ammo vs the needs of your barrel. Look for the lowest vertical dispersion and if you have 2 loads that shoot the same accuracy, the flattest group gets the nod.

Good luck..... and really think about handloading.

Jerry
Click to expand...

I'm already handloading. I didn't have time last weekend because I am posted in Petawawa but my house, Wife etc. are just west of Ottawa so I guess in a way I live a nomadic lifestyle. I was just debating on if I was smart on purchasing a variety of 168gr projectiles or if I should have mixed it up.

As for Berger....@ 65 bucks a box, I'll wait until my technique comes along.

Thanks a heap!

~ Frank
 
shell_guy said:
Hand loading is the way to go.....I would be trying the 185 match hybrid target or the 168 match hybrid target. That being said, with a 20" barrel I would really push the 168 match hybrid target due to the high BC and reduced weight for increase velocity, with a 20" barrel you are at a disadvantage as far as velocity goes to start with so the lighter bullet will help with keeping the velocities up for when you decide to reach further out.
Click to expand...

165-168 it is for the time being. Although I didnt place high, all my rounds were touching paper even at 600 metres. (I still shot better than 5 other guys at least)
 
klink1983 said:
I'm already handloading. I didn't have time last weekend because I am posted in Petawawa but my house, Wife etc. are just west of Ottawa so I guess in a way I live a nomadic lifestyle. I was just debating on if I was smart on purchasing a variety of 168gr projectiles or if I should have mixed it up.

As for Berger....@ 65 bucks a box, I'll wait until my technique comes along.

Thanks a heap!

~ Frank
Click to expand...

Where are you buying your Bergers???? That's pricey.

If you can find them, match bullets from most any brand will work at this level. The Nosler competition has worked well and is a Sierra clone for the most part. Some the Hrn products can also work well.

If necessary, load up some Hrn SST's as they are a very accurate bullet.

Peak accuracy is great but not the end all. You need consistency. If you can't believe that the shot is out because of wind, you are now spending way too much time, money and frustration chasing ghosts.


As much as top components are expensive, missing is even more spendy....

Jerry
 
With the BC of the 168 Hybrid Match Target you should have no problem at 1000m and you don't even need a hot load to keep it supersonic at 1000m. I personally load it with VV N550.
 
Right now Im shooting Hornady 225 HPBT out
of a Broughton 5c 1-10 @ 3200 fps and they shoot laser straight no problem at all. My poor barrel :(
 
I shoot .30 cal. Hornady Moly-Coated 178gr AMAX bullets out of a 26.5" AMTU contour McPhee stainless barrel with a 1 in 11.3" twist at 2730 fps..............I get excellent results............
 
I find that 185s shoot better at 800-1000 yards, but out to 600 yards you might just as well do better with a lighter bullet and don't rule out as light as 150 grains.

I'm with Jerry on the advice to stick with what shoots most accurately at close range because that will probably be best out to 500-600 yards unless the wind gets tricky, then you should revert to the 185s even if they are not quite as accurate at close range.

The 168s are not know for their high BC so I wouldn't be surprised that you get better results with a 155 anyway.
 
BadAsMo said:
I find that 185s shoot better at 800-1000 yards, but out to 600 yards you might just as well do better with a lighter bullet and don't rule out as light as 150 grains.

I'm with Jerry on the advice to stick with what shoots most accurately at close range because that will probably be best out to 500-600 yards unless the wind gets tricky, then you should revert to the 185s even if they are not quite as accurate at close range.

The 168s are not know for their high BC so I wouldn't be surprised that you get better results with a 155 anyway.
Click to expand...
The 168 in question is the Hybrid Match Target which has better BC then a 175vld and on par with the 185's.
 
Mystic Precision said:
Where are you buying your Bergers???? That's pricey.
Jerry
Click to expand...

Not that I want to name a shop to make them look bad for their prices because that is not my intent, but Stittsville GC in Ontario had them listed. My guess is it is harder for them to get... *Shrugs*

For now my stock includes 168gr Amax, some 168gr BTHP Match although I am low, and 165gr Sierra GK (accidentally bought on impulse instead of reading the box)

I was touching paper at 600 which satisfies me for now. My issue was part technique on my part, reading the wind, and a lack of a rear bag (as required for this particular shoot for the added challenge).
 
rnbra-shooter said:
Nothing wrong at all with shooting 168 grain factory match ammo out to mid range (about 600). It's expensive, but that's really the only "bad" thing to be said about that ammo.

If you ever want to shoot beyond 600 metres, there are (much!) better choices of bullet to be had, whether you are using purchased match ammo or are making your own ammo by then. But for 600 and closer, what you were using is great.

*FAR* more important that a specific bullet weight, is whether it is a high quality bullet (the Sierra 168 Matchking used in the Norma 168 Match is a high quality bullet). And with a factory barrel, whether or not your barrel happens to "like" or "dislike" a particular high quality bullet (one of the advantages of match barrels is that they will shoot pretty much any high quality bullet well, and are usually *not* fussy)
Click to expand...

For not shooting passed 300m before, and brutally hungover I faired pretty well with the Norma ammunition I shot. To me 168 or heavier makes sense, I have an abundance of it because that was what was available at the time. If ammunition/component availability wasn't always an issue (seems to be country wide) I would have a variety of projectiles.
 
With 1-10 you can shoot whatever you want for weight.

I'm shooting 208gr with a 1-11.25 no problems out past 1000 yards.

The internet will tell you it would fall out of the sky, but it's all keyboard humpers typing that.
 
If I had your rifle I would try a box of Sierra 190 Match and 175 match. the 175 is the 168gn with a better boat tail. Load them about 20 thou off the rifling and shoot to see which your rifle prefers. both will work out to at least 900 yards.
 
From my experience, jumping .020" may get best accuracy at close range, but I find the velocity spreads open up when you jump that far and then you get verticals at long range. To that point I find the sweet spot is closer to the lands.
 
Then their's the common thought that SMKs like mag length....

I'll admit, for some reason I've had a hard time getting SMK's to shoot. I know most would say that is odd. I've tried 20 off and 2.810. I do like the fact they don't shoot as consistant as others, because the other options are cheaper =)
 
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