.220 Swift musings

[jaytee]

So the other day I loaded up some 60 grain Sierra HP's #1375 in my M77 Sporter and shot a very good 5 shot group, around a half inch if I remember correctly and yesterday I decided to load some 60 grain Nosler Partitions with the same powder but different cases. Same case length and same OAL measured from the ogive and seated at 10 thou off the lands. I really had high hopes for this bullet as its actually just a tad shorter then the Sierra, .7880 compared to .7820 which in a 14 twist I really didn't think I'd have stability issues but was I wrong. I didn't even waste the time measuring but it looked like a shotgun pattern. 5 shots in a somewhat circular shape and about 3 1/2 inches, maybe more. Any ideas as to why? I wouldn't think the change in cases would make that much of a difference so it has to be the bullet is the only thing I can think of. What say you?

 

[Tommie]

I had very similar results with that particular bullet. No key holing?

 

[jaytee]

I had very similar results with that particular bullet. No key holing?

Nope just really spread out. I'm wondering if it might have something to do with the weight distribution of the bullets?

 

[Coyotefurharvester]

Requires 1/12 twist minimum.

 

[Gary in MD]

Yea, a 12 twist would probably help.
But those particular bullets have never had a great reputation for accuracy

 

[jaytee]

Requires 1/12 twist minimum.

So why would the 60 grain Sierra's that are 2 thousandths longer shoot a sub MOA group and these pattern like a shotgun? What are the main factors in bullet stability in relation to twist rate, especially when you might be at or close to the upper end of bullet weight for the twist you're shooting?

 

[6MMsteve]

yep 1n12 for the 60s, swift can be a little finicky and primer pockets will go also, I have found the vmax will shoot well in the swift

 

[jaytee]

yep 1n12 for the 60s, swift can be a little finicky and primer pockets will go also, I have found the vmax will shoot well in the swift

That still doesn't answer my question as to why the 60 GRAIN SIERRA'S are shooting sub MOA and the 60 grain Nosler's are awful! Obviously the 1/12 twist doesn't pertain to all 60 grainers.

 

[Tommie]

That still doesn't answer my question as to why the 60 GRAIN SIERRA'S are shooting sub MOA and the 60 grain Nosler's are awful! Obviously the 1/12 twist doesn't pertain to all 60 grainers.

Partition bullets have only one purpose: terminal performance. Each bullet has two lead cores, is more complicated to produce and has more opportunities for factors which adversely affect accuracy. The small diameter the bullet, the more difficult the process. Just the nature of the beast.

 

[Jager]

You certainly wouldn't expect to see that much difference between the two bullets. But you did change brass. It's possible that the second load is making very different pressure than the first.

Also sounds like you shot a single nice group with the Sierra. You'd want a goodly number of rounds with that load, grouping consistently and well, before concluding that that load is a keeper.

If it were me, I'd punt. Go back to the first load, with the Sierras. Confirm that load actually gives you that 1/2 minute over and over. Once you're confident that's the case, go back to the Nosler - keeping everything else the same, including the brass.

What's the load?

 

[jaytee]

You certainly wouldn't expect to see that much difference between the two bullets. But you did change brass. It's possible that the second load is making very different pressure than the first.

Also sounds like you shot a single nice group with the Sierra. You'd want a goodly number of rounds with that load, grouping consistently and well, before concluding that that load is a keeper.

If it were me, I'd punt. Go back to the first load, with the Sierras. Confirm that load actually gives you that 1/2 minute over and over. Once you're confident that's the case, go back to the Nosler - keeping everything else the same, including the brass.

What's the load?

33 grains of IMR 4064, CCI 200's, 2.193-95 case length and 2.405 OAL measured at the ogive. And if I remember correctly when I measured both bullets with my Hornady OAL modified case gauge they were both within 2 thousandths of each other so I loaded them at 10 thousandths off the lands.

 

[FNSafari]

That still doesn't answer my question as to why the 60 GRAIN SIERRA'S are shooting sub MOA and the 60 grain Nosler's are awful! Obviously the 1/12 twist doesn't pertain to all 60 grainers.

Have you measured and compared the bearing surface length of each? The nosler may be just longer enough to cause stability probs in a 1-14 due to its bearing surface length.

 

[6MMsteve]

That still doesn't answer my question as to why the 60 GRAIN SIERRA'S are shooting sub MOA and the 60 grain Nosler's are awful! Obviously the 1/12 twist doesn't pertain to all 60 grainers.

nosler's have never shot well for me in anything, I use them in AR style rifles that's it, if I'm lookin for accuracy it will not be a nosler, now some guys like them and can shoot them well, just not me

 

[M-61]

I’ve always considered Nosler (decades ago when I hunted)
Strictly a ‘hunting bullet’
Now regarding weight. I know these are the same but isn’t 60 grains in a 1/14 right on the edge to start with.
No longer have my swift but in a 222 with 1/14 the groups open up considerably over 52.
I once tried 69 gr and the only thing aside from horrible groups is that 1 of the them WILL keyhole
Then in every BR rifle I have (4) some prefer one make over another by quite a bit, with no reason I can figure out.

 

[jaytee]

Have you measured and compared the bearing surface length of each? The nosler may be just longer enough to cause stability probs in a 1-14 due to its bearing surface length.

I did measure them and the Nosler was actually 2 thousandths shorter then the Sierra 60 grain.

 

[FNSafari]

I did measure them and the Nosler was actually 2 thousandths shorter then the Sierra 60 grain.

Ok

 

[358WCF]

The Swift was designed to use 50 (48?) gr bullets @ c.4000fps in a 14 twist barrel.

Why would you use a Ferrari (even an 85 yr. old one) to haul cinderblocks? Load up some 50s with H4895, RL15, 4064, or even 3031 & rock on.

 

[jaytee]

The Swift was designed to use 50 (48?) gr bullets @ c.4000fps in a 14 twist barrel.

Why would you use a Ferrari (even an 85 yr. old one) to haul cinderblocks? Load up some 50s with H4895, RL15, 4064, or even 3031 & rock on.

I'm trying to develop a deer round and would prefer a little heavier bullet. Now if Nosler made the partition in a 50 grain style then all would be good!

 

[No manches"]

I'm trying to develop a deer round and would prefer a little heavier bullet. Now if Nosler made the partition in a 50 grain style then all would be good!

Re-barrel to a faster twist, or maybe time for a bigger caliber?..
Let me be clear as I currently own two 220 swifts,
And completely love them. I have made the right decision to have a faster twist installed.
1st has a 12twist and second has an 11twist.
My upcoming 3rd will be a 10twist.

 

[357Mag]

So the other day I loaded up some 60 grain Sierra HP's #1375 in my M77 Sporter and shot a very good 5 shot group, around a half inch if I remember correctly and yesterday I decided to load some 60 grain Nosler Partitions with the same powder but different cases. Same case length and same OAL measured from the ogive and seated at 10 thou off the lands. I really had high hopes for this bullet as its actually just a tad shorter then the Sierra, .7880 compared to .7820 which in a 14 twist I really didn't think I'd have stability issues but was I wrong. I didn't even waste the time measuring but it looked like a shotgun pattern. 5 shots in a somewhat circular shape and about 3 1/2 inches, maybe more. Any ideas as to why? I wouldn't think the change in cases would make that much of a difference so it has to be the bullet is the only thing I can think of. What say you?

Jaytee -

Howdy !

Shooting 60grainers from a 24" SS Hart 1-14 5-groove chambered in my " .22-35Remington " wildcat,
I was not able to stabilize and custom 60gr HPs that were longer than .750" . Longer 60gr bullet lengths proved too long to be stabilized by the 1-14 twist. My .22-35 wildcat has case capacity between that of a stock .22-250 and a .22-250AI.

With regards,
357Mag