[GOT_GLOCK]

I have a winchester Mod. 70 .300 WSM Super Shadow, that has a rather peculiar trait. On a cold bore it will shoot approx. 3" hi/left, after a couple of shots 3 or so it shoots to point of aim in .25" 3 shot groups. It will continue to drive tacks as long as the barrel is hot. (all numbers @ 100yrds.) Any Ideas?





Now to the real reason I posted. I was out testing some hand loads for the aformentioned rifle and had a couple of cases come out with what appear to be "pressure tracks" or indentations where the pressure flowed back into the chamber crushing a small path into the exterior of the case while doing so. The loads were with IMR 4064, 150 Nosler AccuBond @ 3230fps with CCI 250 primers. The primers show no over pressure signs, the soot on the neck is about normal for the gun, I had tested this load prior with no known issues like this.



Is this just a fluke, or is there something to be concerned about. I have pretty much ruled out that load as win 748 groups much better in my gun.



pics below:

http://img16.imageshack.us/img16/2843/img0169f.jpg
http://img11.imageshack.us/img11/1058/img0170pu.jpg
http://img10.imageshack.us/img10/4446/img0171dy.jpg
http://img17.imageshack.us/img17/5083/img0173ol.jpg

[GooseGestapo]

#1; either the barrel pad on the fore end is putting excessive presure and as barrel warms the shots are walking or the barrel is over torqued into the reciever and reciever isn't true. I have a Rem.M7 7mm-08 that did the same thing till I removed the toward pressure pad.
#2. The .300WSM is a very thick case which allows it to operate at higher pressures than other cartridges. What you saw is a pressure crease where the drop in chamber pressure before the bullet exited the bore, and residual pressure "leaked" back past the case neck after it had "relaxed". Rick Jamison who developed the WSM line of cartridges reported seeing this. The "fix" is to use slower burning powders. Imr4064 is a tad fast for the .300WSM. Most loaders are using H4350 or slower powders.

[GOT_GLOCK]

barrel is completely free floated from the reciever to the tip of the forearm.

My gun must be a bit finicky then. As I have to use faster powders to get sub 2" groups at 100 yds, and I am looking for groups less than .5"@100. My best to date is with Win748. The factroy loads are Win760, and I have tried IMR4831 whic gave acceptable groups at 100yds but not at 200yds.

All of my reloading manuals also list powders on the faster side of the spectrum, which is a bit on the odd side if they were designed for what I would call super slow powders. 4831,760,4350, retumbo, magnum.

[steve4102]

Yup, switch to a slower powder!

[1858]

All of my reloading manuals also list powders on the faster side of the spectrum, which is a bit on the odd side if they were designed for what I would call super slow powders. 4831,760,4350, retumbo, magnum.

Are you looking at .300 Win Mag load data or .300 WSM load data? :confused: Lyman lists IMR 4350, IMR 4831 and 760 for a 150gr JSP bullet but that's for the .300 Win Mag not the .300 WSM. The fastest IMR powder listed for the .300 WSM in Lyman's 49th Edition is 4350 which is a lot slower than 4064. In fact, 4350 is similar to Reloder 19 so what manuals are you using? IMR 4064 has a burn rate similar to Varget which is widely known to be an excellent .308 Win powder.

As for your cases, the soot on the neck appears to extend well onto the shoulder which I never see on cases fired in any of my rifles including my .300 WSM. Also, it looks like there's a bulge on the shoulder where it transitions to the neck. Does the bolt feel tight when you try to open it after firing a round? If you've got a serious overpressure situation you'd think that the bolt would be hard to open.

I have no problem getting consistent sub MOA 5-shot groups with my Remington 700 Alaskan Ti at 100 yards. I'm using Reloder 22 and 168gr SMK bullets (Norma brass and CCI 250 primers).

:)

[GOT_GLOCK]

actually that load was a dead rip off from the Nosler book.

IMO the lyman book while regared by many as the bible has some of the wimpyest, least performing, lackluster data of any published load data book. While I use it for reference for case dimsions and such, I generally refer to a book from Speer, Nosler, Barnes, or Hornady.

The Win748 load that I tried and seemed to shoot well was from the latest speer book, as I was just looking for some starting points in the 3200fps range.

I'm thinking that it was an under pressure problem allowing the pressure to flow back into the chamber. The primers looked great no flatteing what so ever. Bolt tension was consistent with the factory loads; which soot up the shouler too.

Any one use retumbo in a 300WSM?

[sourdough44]

I keep it simple & use H 4350 with the 300wsm, 165 & 180 grn bullets.

[NCsmitty]

I would be concerned if my brass looked like those shown.
There are several Hodgdon distributed powders that will give good numbers in the 300WSM, including IMR4064.
www.hodgdon.com

I'll add that Alliant's Rel-17 was designed for use in the WSM and WSSM and gives a boost to many bottle neck cases so designed, according to the data listed on the www.alliantpowder.com/ site.


NCsmitty

[SlamFire1]

I have a winchester Mod. 70 .300 WSM Super Shadow, that has a rather peculiar trait. On a cold bore it will shoot approx. 3" hi/left, after a couple of shots 3 or so it shoots to point of aim in .25" 3 shot groups. It will continue to drive tacks as long as the barrel is hot. (all numbers @ 100yrds.) Any Ideas?

I agree with the earlier posts about potential stock interference with the barrel, and that for best accuracy the barrel needs to be free floated.

I have noticed that point of impact changes as a clean barrel fouls, but once fouled, they usually shoot to the same point of impact.

If bedding and starting with a fouled barrel does not cure this, then the problem is that the barrel has internal stresses.

I have one rifle that is particularly bad in this regard, walking at least 14 inches as the barrel heats up. I had not tried cryo treatment, but than may fix it.

[GOT_GLOCK]

Winchester's are semi known for cra**y barrels. Their proof steel is not homogenous enough.

I can guarnatee its not stock/barrel interference; if anything its a bad barrel, might just pony up for a Lilja.

[FROGO207]

One of the members had a good post on telling if the barrel is stress relived, I think it was to do with a Handi Rifle. If the barrel is bad It will not "ring" when tapped after it is removed from gun and suspended from one end. A dull sound is the sound of a stressed barrel. This may be your problem. You may need another barrel to solve your walking pattern.

[Kernel]

Your powder choices are way, WAY, to fast. 748 is so inappropriate, it's laughable. Your bass is giving you hints. Follow them. You need to move WAY up the speed chart. Try Reloader-19, it's ideal for the .300 WSM.

[243winxb]

The neck may have been outside neck turned. The bulge at the neck shoulder junction is from a bushing die, as they dont size all the way to the shoulder. The neck did not seal because of low pressure and neck turning. Speer Manual #8 has a photo with 3 fired case same type as this photo. States, mag. rifles with to much free bore and slow powder can cause the case to collapse. But the whole body of the case gets dirty. Did you wipe your cases before shooting the photo?? http://i338.photobucket.com/albums/n420/joe1944usa/collapsedshoulder.jpg

[243winxb]

I'm thinking that it was an under pressure problem allowing the pressure to flow back into the chamber. Or a lube dent from firing or sizing, were the cases wiped clean? Maybe some cleaning patch left in the chamber?

[GOT_GLOCK]

no the cases were not wipped before taking the photo, the only thing is that I had tried such loads before and noticed no deformation like this; so this was a bit puzzeling.

Your powder choices are way, WAY, to fast. 748 is so inappropriate, it's laughable. Your bass is giving you hints. Follow them. You need to move WAY up the speed chart. Try Reloader-19, it's ideal for the .300 WSM.:rolleyes:

Kernel, if its so inapproiate then maybe you should notify Speer so that they can remove a such inapproiate load from their manuals before someone gets seriously hurt.

[243winxb]

no the cases were not wipped before taking the photo, the only thing is that I had tried such loads before and noticed no deformation like this; so this was a bit puzzeling. Fired brass to clean to be gas leakage i would guess??. So my guess is oil or lube in chamber on firing. Or lube dent when sizing. Very strange.