brass length

[sbhooper]

Why do manufacturers make brass at max length, instead of minimum? It looks to me like they would save lots of money, by forming it to minimum length, instead of max. It would also make it last longer until it had to be trimmed. Just wondering.

 

[Rsadams]

Just my opinion on this but they have to make brass that will fit any chamber. Since no chambers are the same they do almost all things like this so there won't be problems....

 

[ireload2]

Brass is normally made to comply with the SAAMI standards drawings that govern the industry.

 

[NorCalMikie]

Max length brass "may not" be too long for your chamber? Measure your chamber and see for yourself. Most are cut about .020 to .025 OVER max trim length. SO, no trimming needed.

 

[sharps618]

Recently went thru a 1000pc lot of a major manufacturers .308Win, about 8% were grossly under SAMMI length, with less than 2% being 0.020" too long... go figure right.

 

[Liven The Dream]

I have 2 different Lots of .308 Lapua They are much different in weight and neck thickness ??

Possible two different production Run's ?? Different set of Dies ??

It is a mass produced Product I would think it would not be Perfect ???
This is way they sell us all those Tools to get it Right !!

 

[Zero333]

http://bulletin.accurateshooter.com...-chamber-length-with-home-made-modified-case/

Measure your chamber and don't trim as often.

Like NorCalMikie said.. "Most are cut about .020 to .025 OVER max trim length".

 

[NorCalMikie]

I have BR brass that has been fired and sized a BUNCH and no trimming needed yet. (25 to 30 times) Also depends on what type of dies you use. With full length, the neck button will pull the necks on the upstroke. Shoulder bump and neck sizer dies will let you size and not have to trim for a long time. Maybe body size once in a while but still not even close to max trim length for needed trimming. With new brass, maybe trim them all to the same size then watch them for length?

 

[sbhooper]

I get it about chambers and all that. I didn't just start doing this stuff. It just seems to me that it would make sense for the manufacturer to make the brass at trim-to length, instead of max length. I have no problem trimming it, when needed and totally understand the process. Talking millions of rounds of brass, they would probably get a lot more brass out of the product, with the extra saved from each piece. Most of the brass that I have dealt with over the years, is good for about one, or two firing before it is at, or over, max length. Irrelevant to me, but just curious why they are cut so long start with.

 

[MislMan]

All manufacturing has +/- tolerances. I would suspect the manufacturing equipment is set to the middle of the SAAMI spec to account for these tolerances. If set to the max or min dimension then many would be either over or under the SAAMI spec and therefore be rejected. Depending on where in the lifecycle of the manufacturing equipment you are (brand new or wornout cutter edge), your lot of brass could be on either the long side or short side of the set-up. Similar to cutting a chamber with a new or wornout chamber cutter.

 

[jepp2]

Max length brass "may not" be too long for your chamber? Measure your chamber and see for yourself. Most are cut about .020 to .025 OVER max trim length. SO, no trimming needed.

I have often heard this. The only one I ever checked turns out was 0.006" over max trim length. But it was a rebarrel, so it might not be representative of factory barrels.

 

[KevinThomas]

I've taken far more complaints about brass being trimmed "too short" (which it wasn't) as it came from the box. The "trim to" length listed in most manuals is actually a somewhat arbitrary number, being merely .010" under the Max Length dimension. In the case of the 308 Win, 2.015" is SAAMI max, with most manuals listing a "trim to" length of 2.005", which is .010" under Max. The true minimum is 2.015"-.020", or 1.995". People are getting far too wrapped up in this, and it's actually a safety issue, having little or nothing to do with accuracy.

 

[fguffey]

Why do manufacturers make brass at max length, instead of minimum?

The case has two lengths, one if from the end of the neck to the case head and the other is from the shoulder to the case head. reloaders make references to max length, my dies size cases to minimum length and or full length size, if I choose to size to maximum length I back the die off the shell holder when adjusting.

I have always wondered why brass manufacturers did not manufacturer brass for reloaders that know what they are doing. If I had a choice I would purchases brass that would not allow the bolt to close. I had rather purchases brass that had to be sized to fit the chamber. Most other reloaders choose to fire form, chamber a round and then pull the trigger and then become a fire former, like that is all a reloader has to know.

Again: I have a 30/06 chamber that is .016: longer than a minimum length/go gage length chamber from the shoulder of the chamber to the bolt face, I could ask how could I off set the length of the chamber with a case but I would be wasting my time because reloaders are fire formers.

F. Guffey

 

[Comrade Terry]

....^^^^....^^^^....^^^^....^^^^........^^^^....^^^^....^^^^....^^^^....^^^^

I like the moniker someone bestowed upon him the other day. "Goofy".

 

[chop house]

Like NorCalMikie said.. "Most are cut about .020 to .025 OVER max trim length"

and most brass, as also pointed out**, is shorter than recommended trim length, which itself is nominally 0.010 under max trim length.

so there's a 1/32" margin at the middle of the bell curve.

add... **most brass I have used has been. but then again i have never sprung for lapua.

 

[Webster]

Why do manufacturers make brass at max length, instead of minimum? It looks to me like they would save lots of money, by forming it to minimum length, instead of max. It would also make it last longer until it had to be trimmed. Just wondering.

Just went to the SAAMI spec website. Compared the case drawing to the chamber drawing for a 6mm Rem. The case neck is .3508" long. The area of the chamber machined to neck diameter is .3778" long. So there is .027" extra room for the case neck to fit in. There is also a .016" long taper from the chamber neck dimension to the throat diameter. If you don't care how long the neck is you would never have to trim it.

 

[foxguy]

I have BR brass that has been fired and sized a BUNCH and no trimming needed yet. (25 to 30 times) Also depends on what type of dies you use. With full length, the neck button will pull the necks on the upstroke. Shoulder bump and neck sizer dies will let you size and not have to trim for a long time. Maybe body size once in a while but still not even close to max trim length for needed trimming. With new brass, maybe trim them all to the same size then watch them for length?

This bring a question to my mind, if you have measured your chamber and find it .025 over the SAAMI max, Do you try to maintain a new max brass length .015 shorter than your Measured Chamber Length?

I don't believe I have ever seen what the recommendation is to stay below the measured length.

 

[Webster]

This bring a question to my mind, if you have measured your chamber and find it .025 over the SAAMI max, Do you try to maintain a new max brass length .015 shorter than your Measured Chamber Length?

I don't believe I have ever seen what the recommendation is to stay below the measured length.

I think most of us trim to the length in the reloading manual. Not complicated.

 

[NorCalMikie]

One issue that you "may" run into is carbon buildup in the neck area between the neck and the end of the chamber cut. Just more to think about.

 

[sbhooper]

I think most of us trim to the length in the reloading manual. Not complicated.

This is all that I have ever done. Those numbers have worked forever, and I see no reason to mess with them. I am not a benchrester, but I have never noticed a difference in accuracy using casings that barely let you close the bolt, vs ones that are freshly trimmed to minimum. I use only Lee trmmers-no muss, no fuss, just consistent trims.