case length?

[TREERAT]

making .358 win from 30-06 brass, I can make the neck as long as I want, but my question is if I trim EVERY time I load these cases, can I use them at MAX chamber length?

[felix]

Yes, unless your chamber is out of spec. The only way to tell is with fully fire-formed cases, and using finger pressure in seating a 358 bullet/boolit. ... felix

[Shiloh]

How long is your chamber??

I have a few of these in different calibers. Then you will know. If your chamber is long, you can leave the brass long. If you trim to recommended length without knowing, your brass may be shorter than it needs to be.

There are other homemade ways to check, but these were convenient and I had to order from them anyway.

http://www.sinclairintl.com/product/11241/Case-Gauges-Headspace-Tools

Shiloh

[TREERAT]

book says case length is 2.15, trim is recomended -.10 so 2.05, if the chamber measures 2.19, if I trim EVERY time they are loaded can I trim at 2.19 or do I still have to leave a little room

[captaint]

So try trimming to .217 and maybe you won't have to trim every time. What kind of rifle are you using?

[Wills Point Pete]

You can indeed trim to the length of your chamber IF you trim every time. Now the bad news of that idea is that sooner or later one or two cases might slip through, untrimmed.

Of course if that happens with a moderate pressure load you'll just have increased pressure and maybe a missed target. If you are at max pressure you can face problems from having to hammer the bolt open to a wrecked rifle. After all, Murphy was an optimist.

[TREERAT]

in a ruger m77 mk11, low velocity 1200-1400,

[Larry Gibson]

in a ruger m77 mk11, low velocity 1200-1400,

With loads like that you should never have to trim if you neck size only. I would make the necks as long as possible to fit the chamber neck length perfectly. You can easily do a chamber cast of simply trim a formed case to 2.30 and see if it will chamber going gently on closing the bolt. If it doesn't then trim .005" off that case and try again. Keep trimming the .005" and trying until the bolt closes with no feel of the case. Then form 5 cases and trim to that length. If they all chamber easily then I'd call that the max case AOL for that rifle. Then form the rest of the cases and trim to that length. You should lose a couple thousands on fire forming that case as when the case body expands out it most often sucks some of the neck back in.

Again neck size and with those low powered loads you should not have to trim. Should you have to FL or partial FL the cases down the raod then trimming will probably be necessary.

Larry Gibson

[TREERAT]

I am partial length sizing. so my thinking was if I trimed to max after sizing, that my cases will always shorten one to two thousands when fired. then lenghten back out again when sized, then checked and trimmed if needed to be at max again. and even at this low velocity my powder and charge will reliably fire form.

[Larry Gibson]

TREERAT

Your plan sounds good in theory but it doesn't quite work out that way. You may get away with it for a few firings but it will catch up to you. The .358W is a minimal taper case based on the .308W. When fired the case will expand just forward of the web at what is called the expansion ring. Even when "partial sizing" a minimal tapered case the FL dies will squeeze in the expanded case at the expansion ring. It pushes the brass forward and it flows into the neck. That's where the trimming comes from. Eventually the case head will show incipient head seperation. With the mild loads you are using that may be a few firings down the road but it will happen. Given the effort used to form the cases and the cost of new commercial cases. the additional cost of a real neck size die is minimal and well worth the expendature. I still advise getting a neck size die and using it. The cases will last a very long time that way.

Larry Gibson

[runfiverun]

you could try taking the primer punch out of your 38/357 sizer die and use it as a neck sizer......
i use a taper sizer for the 38 to neck size my 308 win necked up brass.

[Shiloh]

TREERAT,

Good advice from Larry Gibson.

Trim your cases to 2.10 See what they do from there. At the velocities you are running, your cases will probably last a long time, and probably won't stretch much, but measure them. If there is no or minimal stretch, leave them a little longer.

Buy a neck sizer. I have several collet neck sizers from LEE. I have oversize mandrels for my specific purposes.

I have .30-40 Krag and .30-06 cases that have been fired dozens of times. The chamber of the my Krag is so long that new brass is way short. I trim to keep things the same. With the mild loads that I fire brass lasts a long time.

Shiloh

[Rodfac]

Just another thought here...maybe Larry and Shiloh would care to comment...I've found with bottle neck case loads in the range you are considering...ie: 1200-1400 fps, that after the initial trimming, very little additional trimming is necessary.

What does happen, after a couple of firings, is that the case shoulder is set back producing a head space problem. This is evident by the high primers on fired brass and is measurable in my Wilson case length gauge. One solution commonly suggested is opening up the flash hole. This works but has always seemed to me an accident waiting to happen if I forget and mix the brass in with full power loads. I've marked the cases changed in this manner with Magic Marker, in times past, but have discontinued the practice for the above mentioned concerns.

As to your main premise, that of trimming to maintain maximum length; I've found that in my loads, it makes no real measurable difference on target. I trim to minimum length allowing more loads before I have to do it again. I rarely crimp on rifle loads so getting them absolutely the same length is not a real factor. Even .30-30 loads, with proper case neck tension, don't need to be crimped.

The only case that I've found to date that has some peculiarities is the .30 Carbine. Even with gov't brass, some stretch a lot more than others and the difference in brass hardness can even be seen on the case bulge at the expansion ring. I keep all of my Carbine brass trimmed to minimum length, per the CMP article suggestion. In any semi-automatic weapon, an overly long case can lead to firing out of battery...ie. the bolt is not completely locked. The results can be catastrophic.

Just MHO, Rodfac

[Larry Gibson]

Comments added in bold, Larry Gibson


Just another thought here...maybe Larry and Shiloh would care to comment...I've found with bottle neck case loads in the range you are considering...ie: 1200-1400 fps, that after the initial trimming, very little additional trimming is necessary.

No additional trimming is necessary with a NS die is my point.

What does happen, after a couple of firings, is that the case shoulder is set back producing a head space problem. This is evident by the high primers on fired brass and is measurable in my Wilson case length gauge. One solution commonly suggested is opening up the flash hole. This works but has always seemed to me an accident waiting to happen if I forget and mix the brass in with full power loads. I've marked the cases changed in this manner with Magic Marker, in times past, but have discontinued the practice for the above mentioned concerns.

I've been using cases with the flash holes drilled to alleviate this problem for many years. I use a #28 drill which is the largest to use for LR primers. I've not found it difficult to keep them seperated. If one does a case inspection while cleaning the primer pockets the larger flash hole is very noticeable and can't be missed. I've also ran tests on cases with flash holes drilled working up to full power cast bullet loads in the 2000 fps range. This was with the .308W using 311291 and 4895 with dacron fillers. There were no pressure problems with the WLR primers what so ever. Measured pressures were the same as with normal flash holes. However, testing such cases with full powered Jacketed loads was not done so current conjecture seems to be to mark them and keep them seperated.

As to your main premise, that of trimming to maintain maximum length; I've found that in my loads, it makes no real measurable difference on target. I trim to minimum length allowing more loads before I have to do it again. I rarely crimp on rifle loads so getting them absolutely the same length is not a real factor. Even .30-30 loads, with proper case neck tension, don't need to be crimped.

Case necks that fit the length of the chamber neck keep the bullet more concentric and also prevent riviting (swaging out) of the bullet into the unsupported area. This most often occurs with softer alloys in higher pressure/velocity loads. Also when small amounts of fast burning powder are used which "kick starts" the bullet on it's way. If the alloy is swaged out into the unsupported neck area then it has to be swaged down again as it enters the throat. This most often unsquares the bullet base or can strip a small "donut" off leaving it in the chamber neck ahead of the case mouth. None of this is conducive to good accuracy. If TREERAT is forming the cases and trimming to any desired length he might as well trim them to fit the chamber neck length in the first place. Once trimed back farther he can't put back on any brass.

The only case that I've found to date that has some peculiarities is the .30 Carbine. Even with gov't brass, some stretch a lot more than others and the difference in brass hardness can even be seen on the case bulge at the expansion ring. I keep all of my Carbine brass trimmed to minimum length, per the CMP article suggestion. In any semi-automatic weapon, an overly long case can lead to firing out of battery...ie. the bolt is not completely locked. The results can be catastrophic.

My experience with loading the .30 carbine goes back to '67. I've loaded thousands of them with cast bullets. One must measure and trim the cases after sizing. They will shrink when fired and grow again when sized. Once trimmed to the correct AOL I've never had to trim them again. I'm not sure exactly why but such is the case (pun intended). I've used a standard RCBS FL die and a CH FL die for years but have used a carbide sizer the last 15 years or so. They can be adjusted to partial resize for minimal sizing for one chamber.

Just MHO, Rodfac

[DLCTEX]

I like the Lee collet neck sizing die. No lube necessary, long case life, and no stretching of cases.It has really extended the case life of my 22 Hornet brass and probably my 30-30, but I haven't reloaded these enough to know yet.The only draw back to neck sizing is when loading ammo that may be fired in multiple guns. I have to keep my rifle and pistol ammo for 22 Hornet separated. I have been considering having both rechambered to K hornet, using the same reamer, possibly making my ammo interchangable.

[Shiloh]

Neck sizing is a concern for those of you firing the same brass in multiple firearms.
Chambers vary from gun to gun even from same model, same manufacturer.

Mine is all used in the same firearms.

Shiloh