7 WSM vs. 300WSM at 1000yds

[Guest]

I'm looking into building a new long range rig on the WSM case and I've narrowed it down to the 7mm shooting the heavy 175-180gr VLD style bullets or the 300WSM shooting 190-220gr VLD style bullets.
I wondering which will buck the wind better , a slightly heavier bullet with less BC and same velocity vs. a lighter higher BC bullet at the same velocity. lets say
7mm 180gr Berger VLD at 3000fps BC of .698
or 210gr Berger VLD at 2900fps BC of .640
out of the 300 , the velocities are just a guess at what I could get out of a 28-30" barrel
All the brass would be 300WSM Norma to start with

Which bullet would be best suited for 1000yd work on small varmints and targets

 

[trader388]

I'd tend to think the 180 would be the better choice. I've seen it stated here a few times that the 190gr is about the max you can fit into the 300wsm...and i think that the 300wsm and 7wsm have the same capacity?

I was considering the 300wsm vs the 300wm...but now I am down to the 7wsm vs the 300wm.

[ 03-11-2004: Message edited by: trader388 ]

 

[*WyoWhisper*]

JD,
your gonna be hard pressed to get those velocities your after.. you gonna nee a long barrel for that....
you may be able to get that from the 7mm but I doubt it ( not sure though ) you'll get that much from the 300WSM and the 210.. you might though....

 

[BountyHunter]

JD

on the 7WSM, stay with 1-9 twist, also sierra is supposedly coming out with a 175 gr 7mm this year.

You can get 2900 with 210s but you need the 30" barrel and best accuracy will probably be 2850-200 max. Now one guy I know with 210s, Win brass, heavy loads of MRP is going over 3000 in his gun, but he is the only one that is able to do that and he has shot some 5-6" groups in competition. However, I have done 2900 easily with the Win brass which I think has a little more capacity than the Norma.

JLK makes a very good 190 and 210 bullet also. Very good tolerances and high BC. I like them better than Bergers but everyone has their pickss/

BH

 

[Jake in NC]

.. Just for reference..
... I have a 7WSM on a customized Winchester action with a 28" Spencer 1-9tw Heavy Varmint barrel.. With 162gr AMax's (BC=.625) I'm getting around 2950fps.. The same bullets from a 7Mag from a Sendero were around 3100.. The stated 3Kfps w/180gr projectile may be a little optimistic with these cartridges but keep in mind I'm still doing load development.. Another powder (H4831sc & RL22 so far) yet to be tried may give better results.. d:^) JiNC

 

[trader388]

hunter - do you know where to find the BCs on them JLKs? Particularly the .30 calibers and 7mm calibers.

 

[Guest]

Like I said , I don't know what velocity I would be able to get with these cases I was just giving out a number but I figured that as with most rounds that use the same case with differant diameter bullets of the smae weight that the larger diameter bullet will tend to get better speed.

My gun is being built on a long action so I'll be able to use these realy long bullets and still feed from the mag without getting the bullet down into the powder area.

I realy just looking for the better of the two for bucking the wind at the 1k or better.

Berger VLD's and Sierra MK are the onlt two match bullets I have delt with , where can I get info on the JLK's and Lapua bullets ?

 

[Hunter66654]

Trader, the BC's for JLK bullets are as follows: 7mm-168gr= .690, 7mm-180gr=.738, 308-175gr =.545, 308-190gr =.602, 308-210gr =.665 This info came from Jimmy Knox of JLK bullets.

 

[Mysticplayer]

From the guns that I have built and shot at 1KM, I would definitely go with the 7mm for these reasons.

If competing, weight and recoil will be issues so barrels can't be super long. Fatigue with the heavier bullet will affect groups. The WSM case is getting a bit small for real heavy 30cals. Perfect for the heavy 7mm.

Accuracy may not be at the vel level you need to make the 30cal 'work'. With the 7mm, even if it ends up being slower, the high BC will help at 1KM. Most barrels shoot their best at less then max pressures.

Compare the effects on a ballistic program. I bet you will find that BC plays a much larger role then vel when it comes to wind drift. drop is of little importance as you will know how far you are going. Misjudging the wind by a few MPH is pretty common and the higher BC bullet will shoot through those conditions better.

Jerry

 

[John Burns]

BC is the controling factor in wind drift. If two bullets have the same BC they will drift exactly the same no matter what weight each bullet is.

 

[Aussie]

John has it right . BC is the important factor , not weight . Time of flight is also important . IF BC is the same then velocity will govern which bullet drifts (and drops) most .

 

[Magmaniac]

Boyd Heaten shot this same bullet for matches he pushed them around 2,800 and for hunting around 2,950, not sure about barrel length but I beleive it was about the same length as what you stated.

 

[BountyHunter]

JD

I shoot the 300 WSM in HG and I can take a 210 JLK to around 2875 with good accuracy in a 30" Spencer barrel.

I am building a new 300 WSM with 30" Broughton barrel with the "5C rifling". It is the radiased lands like the Obermyer and Rock barrels. Broughton barrels are really kicking but lately and people are getting higher MV due to the rifling. This gun will be throated to shoot the 187 BIB flatbase bullets. Jim Hardy in NC is getting 3125 MV with 30 Broughton barrel in 300 WSM and Norma brass now and great accuracy.

This setup requires special long throat reamer as the bullet has pressure ring that must be in the neck.

Based strictly on the BC, the edge is to the 7MM WSM as I said before and I would look at the Broughton barrel with 1-9 twist if you want max MV and accuracy.

BH

 

[DMCI]

This is what I am getting out of a 28" 1 in 9 Lilja 3 groove 7mm WSM:

Win LRM Primer
Berger 180 VLD
Win Cases
VV N165 Powder

Grs. Velocity(SD)

61.0 2737

61.5 2757(6)

62.0 2780 Group size: .313"@100 yards 5 shots.

62.5 2800

63.5 2858(10)

64.0 2890(15)

75.3*F
29.75 in Hg
49.7 RH

Looks like more investigation for accuracy only needs to be made for loads from 61.5 to 63.0 Initial indications are that rounds have very excellent consistency.

On a second occasion, we visited the range with 180 Berger VLD and VV N165 but with F215M, a magnum match primer:

62.0 2834(9)
62.5 2866(8)
63.0 2895(7)
63.5 2916(6) Group size: .401 @ 100 yards 5 shots.

85.0*F
30.2 in Hg
25% Humidity

Interesting in this case the best group was the heaviest load. Some minor primer extrusion around firing pin, nice bark, light to medium recoil even with Break and 15# gun.

With WLRM primer, best group was 62.0 to 62.5. This is an excellent mid-range target load.

I think for now the F215M load will be the one loaded for target shooting.