Brass trim question

[JFK]

I’m new to reloading and getting everything ready to begin loading 110gr TTSX for my 270win. I have 100pcs of new Hornady brass. I plan to full length size, chamfer and debur before loading it. This is a hunting rifle, and while I want accuracy I’m not chasing it the same way bench rest guys do. I’m trying to keep things safe and simple.

My question relates to case length. Barnes load data for 270 win says case trim length is 2.530. I have measured 50 of the new cases and they are extremely uniform, with most at 2.5350 and a few at 2.5345 or 2.5355. I understand these dims are well under max case length of 2.540 so would be safe to start working up a load at current length.

How important is it to have every case dead nuts the same length? Are a couple thousandths going to impact accuracy and consistency? Again, this is a hunting rifle and I only shoot to about 300 yards most of the time.

How important is it to follow suggested case trim length from reloading data, assuming I’m within .005 of what they suggest and we’ll within SAMMI spec?

 

[rayporter]

you are good to go.

yes for benchrest all cases MUST be the same length, but you wont know the difference.

that trim back length is so you don't have to trim for a long time.

now are you sure you need to full length size them? if they chamber it will do no good.

 

[WestexSBK]

Your brass will grow after firing. Size, load, shoot, and measure. Pick the shortest you have and trim to that length. Without other case prep disciplines you won’t see a difference in your cases varying a couple thou here and there.

If your going to FL size use a good quality die that isn’t over sizing. Bump the shoulder .002”. Goodluck

Joe

 

[JFK]

you are good to go.

yes for benchrest all cases MUST be the same length, but you wont know the difference.

that trim back length is so you don't have to trim for a long time.

now are you sure you need to full length size them? if they chamber it will do no good.

Probably don’t need to full length size them but only have a full length die. They chamber just fine. I’ll probably end up getting a neck only die at some point after they are fired, but the current plan was to FL size them for first loading just in case a neck had been banged out of shape during delivery to me. In reality it’s probably overkill but it will be good practice setting up the sizing die if nothing else.

 

[idaho-shooter]

Suggest after first firing of new brass for a hunting rifle: full length size and trim to 0.020 under spec. Now you should be set for a couple firings before you need to trim again.

 

[rayporter]

back your fl die off half a turn and you wont bump or fl size the case but the necks will get rounded out. the case will then be formed to your chamber and can be bumped to near perfect size. I take some mica and put a dab on the necks so I can see how far down the neck it being sized. you only need sized half way down. sometimes you can back off the die a whole turn.

occasionally the die will touch the side of the case and lengthen the case a thou, which actually helps the case fit the chamber.

if you bump .002now you will actually make the case too short and it will stretch.

you must wait till it fits your chamber before bumping and this needs a firing. sometimes this can take a couple of shots. I have seen guys bump before it fit the chamber and then ruin brass.

 

[muddydogs]

Yep your case length is fine but I would point out that the time you wasted measuring every case and worrying about case length could have been spent just trimming the bass and being done with it. I trim all my brass every time it gets loaded, I don't worry about measuring pieces to see if there two long or sorting by length. Trim the brass, watch for pieces that don't get trimmed so they can be measured to make sure there not to short and load away.

 

[wapitibob]

With od and id chamfers of the case mouth, the end of your brass is sitting in space, touching neither the bullet nor the chamber wall. Worrying about .002 oal will just give you grey hair.

 

[JFK]

Appreciate all the info.

I’ll throw another question out there. I bought the 100pcs of Hornady brass thinking it would be best to start fresh with consistent lot number. I do have at least 100 pcs of once fired Barnes (Remington) brass. Fired from my rifle but not the same lot #. You guys think it would be better to start with the stuff already fired from my rifle or stick with the new brass?

 

[Doghed]

My opinion is use the fire formed stuff and get good with your tools and methods.