1 in 13" Twist 300 Win Mag

[gzig5]

I just put the bore scope in down the barrel of my Rem 700BDL 300wm and it is kaput. I have a couple extra Krieger 13 twist barrels from my Palma gun that I will never get through. Cutting one for 300WM and threading it on seems like the easy button to keep this rifle in the field. I will be doing the profiling and chambering work. If I have to buy another barrel for it I think I'd rather build another caliber and that will incur extra cost. So, has anyone run a slow twist 300wm like this and if so,what heavy bullet would it handle? How high of a BC or SD can I get? I shot 175MK in these with the 308 cartridge but they aren't especially sleek. I know the long, high BC bullets will be a challenge but if it would handle 190/200 gr Partitions or something like that, that would satisfy me. The JBM calculator seems to like a 180 @ 2900 but has the 200gr 1.35" long bullet @2700fps on the edge (yellow).

I'm well aware that this is an unusual approach, but I'll only be out my time and a reamer rental if it doesn't work out. It should shoot the 150-175 class bullets very well which is real life will handle anything I'm likely to hunt. May get a chance at an elk someday and the heavier class bullet would be nice to have. If I don't do this, I'll probably end up selling the rifle.

 

[rsmithsr50]

I think you are asking for trouble, and truly limiting the 30 wm.
sell a blank and buy a 1/10
see if a local dealer will let you trade plus cash

 

[rsmithsr50]

look for a new take off bbl

 

[Walt Krafft]

I did one for a pd hunter. 125 Sierras were steppn-n-fetchn. Quite spectacular from what he said.

 

[gzig5]

These are barrels chambered for an RPA2000 action with about 500 or less rounds on them. Not much calling for them though they could be re-trheaded. A takeoff crossed my mind but probably would have to be set back and then I still have a factory barrel after all the work.

I don't see how I'm asking for trouble, if a 12-13 twist 308win will stabilize 180's from 600-1000yds? The extra velocity will help a little. I'm just curious if there's any real life experiences with this twist on the 190-200 bullets. It is a hunting rifle, not a 1000yd benchrest gun.

 

[MagnumManiac]

I tried one several years ago, best bullet that performed were 155gr Sierra Palma match bullets. Tried 150gr BT's and 150gr AB, they grouped well but these bullets erode barrels fast as I discovered.
168gr match bullets would stabilise one day and not the next.

Cheers.

 

[Laurie]

Not too many years ago when the 185gn Berger LRBT was a new kid on the block and was only just starting to be called the 'Juggernaut', and before it was decided that Sg values of 1.5 or higher were ballistically optimal, one Bryan Litz who had designed this excellent model, was shooting it in regional and national US-rules (any bullet weight) Palma type matches in 308 Win with a 13 twist barrel. And he won matches too, not a few of them. Bryan wrote at the time that 13 was pushing this bullet length and that 1 in 12" was optimal which he rebarreled to the following season. Now, you need 11.4 twist to fully stabilise this bullet in the 'middle case' situation it's said.

As always, where and when you use this match bullet counts for a lot - if in summer temperatures and up at a bit of altitude, you'll likely shoot it well. The old 190gn Sierra MK is another mid-weight 308 match design you could get away with if the ambient conditions suit. At 1.353" OAL and 2,950 fps MV from the 300 Win Mag, you're down at 1.25 Sg in 'standard conditions' (sea level on a typical atmospheric pressure day / 59-deg F). If you're a couple of thousand ft ASL and it's 80 degrees outside, that rises to 1.39 and you'll shoot the bullet just fine even if you do increase drag a bit over an optimally stabilised situation.

For expanding type bullets, the 180gn Nosler Partition is fully stabilised in this twist in all but very adverse low altitude / low temperature conditions. Millers Rules (which your JBM uses) says the 200gn version's 1.356" OAL and say 2,850 fps MV provides 1.29 Sg in standard conditions, again OK with a couple of thousand ft altitude / 80F etc.

However .... Miller was written for boat-tail bullets which need more spin than flat-base designs and I'd say the 308 Partitions are much closer to FBs than BTs. There is just a tiddly little incipient boat-tail on these bullets that helps seating in the case-mouth but probably barely affects their in-flight behaviours. As a rule of thumb, whatever twist rate provides an adequate / optimal / whatever Sg value with a BT bullet, you can add 1.0 to it for an FB model. Miller says 1 turn in 12" gives 1.52 Sg for the 200 Partition at 2,850 fps in standard conditions, so if you assume it's nearly a flat-base, 1 in 13 will give an equivalent degree of stabilisation. I'd reckon you're good to go with this bullet.

 

[DaveTooley]

I had a 1-14 that shot BIB 187's great. Sg of about 1.1
I shot that barrel from Quantico VA to Byers CO with no problems
It would not handle a 200 gr SMK. I never tried 190's, probably should have.
I would think your 1-13 would be fine with most conservative designed bullets up to 200 grs.

 

[gzig5]

Thanks for the replies gentlemen. It gives me the confidence to give it a try. Worst case I'll have to stick with 165-180gr bullets, but there are some pretty good bullets in that range. Using Berger's calculator at 1000ft, the 185 classic hunting looks pretty good at 1.4 and the 210VLD would be 1.11, which is probably not working all the time. I should be able to find a something in the 180-190 range that will shoot.

 

[PhilKeil]

I have a very good friend who did a 300 rum in a slow twist shilen. it was very accurate and he tended to shoot light bullets very fast i dont think he went over 150 gr bullets. Lasted quite a few years and he shot it a lot.

 

[Rdlningcltchdmpr]

I just put the bore scope in down the barrel of my Rem 700BDL 300wm and it is kaput. I have a couple extra Krieger 13 twist barrels from my Palma gun that I will never get through. Cutting one for 300WM and threading it on seems like the easy button to keep this rifle in the field. I will be doing the profiling and chambering work. If I have to buy another barrel for it I think I'd rather build another caliber and that will incur extra cost. So, has anyone run a slow twist 300wm like this and if so,what heavy bullet would it handle? How high of a BC or SD can I get? I shot 175MK in these with the 308 cartridge but they aren't especially sleek. I know the long, high BC bullets will be a challenge but if it would handle 190/200 gr Partitions or something like that, that would satisfy me. The JBM calculator seems to like a 180 @ 2900 but has the 200gr 1.35" long bullet @2700fps on the edge (yellow).

I'm well aware that this is an unusual approach, but I'll only be out my time and a reamer rental if it doesn't work out. It should shoot the 150-175 class bullets very well which is real life will handle anything I'm likely to hunt. May get a chance at an elk someday and the heavier class bullet would be nice to have. If I don't do this, I'll probably end up selling the rifle.

1-13 will be great. As far as elk the 130ttsx barnes will be the ticket for sure. You will be happy with 13twist.

 

[10at6]

You are GTG. Set it up for a 155 Scenar seated just above the neck/shoulder. Awesome game bullet and won't give up anything inside 7-800 yards. I would be looking for about 3300 FPS with H-4350. Or H-4831.
The 130 Barnes would not such either

 

[markgrabowski]

Can you eject a fired 300wm case from that actions port? (Long enough?)

 

[dougridgeore]

Had a 12 twist on an 300 WSM-F open gun to try and shoot 185 juggernauts that was a bad idea ..that brand new barrel is still sitting in the pile of other mistakes I’ve made over the years and come to think about it? It is parked right next to the brand new 9 twist for shooting the new 230 grain A tips... that was a more recent mistake...going back about 15 years ago when I was still shooting off my elbows I built a 12 twist 300 WSM for shooting 190 SMK’s. That sling gun is still intact and it still shoots well and just last week I put a scope on that gun and shot it using 200 20x Bergers it did pretty good.... one hole group at 100 yards? Have not tried it at distances however?
My advice after making several expensive mistakes stick with 10 twist.

 

[Rdlningcltchdmpr]

Had a 12 twist on an 300 WSM-F open gun to try and shoot 185 juggernauts that was a bad idea ..that brand new barrel is still sitting in the pile of other mistakes I’ve made over the years and come to think about it? It is parked right next to the brand new 9 twist for shooting the new 230 grain A tips... that was a more recent mistake...going back about 15 years ago when I was still shooting off my elbows I built a 12 twist 300 WSM for shooting 190 SMK’s. That sling gun is still intact and it still shoots well and just last week I put a scope on that gun and shot it using 200 20x Bergers it did pretty good.... one hole group at 100 yards? Have not tried it at distances however?
My advice after making several expensive mistakes stick with 10 twist.

I'll give you $100. For that crappy mistake gun.

 

[dougridgeore]

Thinking about all the mistakes and just remembered the two 7 mm barrels custom made ($expensive). 3 groove, 8 twist for shooting the Berger 195’s then the 197 SMK’s...guess what neither barrel 1.250” x 32” would even come close to a 9 twist and 180 hybrids. Just my advice....generally when everyone is shooting a particular twist barrel and a particular bullet at a particular velocity usually there is a reason and trying to gain a small advantage over the standard is only going to cause you to have less money and a huge pile of bullets and barrels you can’t even give away