.308 Winchester Seating Help...

[Flea21]

Ok, so Ive reloaded .308 Winchester for a little while now and have found that my rifle, Remington 700 SS 5R MilSpec, seems to really like around 43.0-43.5grs of IMR4064 with Winchester WLR Primers and Sierra MatchKing 175gr HPBT with Lapua Brass. (Fyi: I havent really loaded hotter than 43.5 because I dont want to get these loads too hot and again, it seems to work, but thats the hottest ive gotten to.)

Now that Ive gotten happy with the accuracy of this load with just using the book reloading specs, I want to tailor a round specific for my rifle. Following are the measurements I have from my chamber...

2.052 Max Chamber OAL
2.918 Max OAL (Touching Lands)

My thoughts are to stretch my brass from firing it to around 2.045 and have my tim length to 2.035 instead of the book length of 2.005.

Also, I played with OAL of loaded ammo to be seated just off the lands by about 0.010-0.015 to allow for variances in Sierra MK projectiles which brings brings me to an OAL of 2.905.

I plan on loading this with my current recipe that has proved to perform very well from my rifle so far.. Hopefully, It will get better with the new seating depth.

Can someone here who loads .308 Winchester give me their opinions on these numbers and also give me some advice on loading specific ammo for my rifle? Thank You.

 

[rduckwor]

Sounds like it works. Go for it. I typically load 175SMK's to about 2.85 and the Berger OTM's to 2.9 as my throat is just like yours. LONG!

 

[Flea21]

Sounds like it works. Go for it. I typically load 175SMK's to about 2.85 and the Berger OTM's to 2.9 as my throat is just like yours. LONG!

Thanx Buddy... Thats what im goin to do then. My HS Precision DBM has a max OAL of 2.855 so these are gonna be single shot loads unfortubately but hopefully more accurate than my last ones at 2.800 which were shooting .25-.75 MOA as they sat.

 

[UrbanSi]

With the long throat on most Remington rifles you should be able to get away with it, if that's just what you are trying to do...

But, the only real advantage to this is how your rifle reacts to jump or no jump.

I think for the most part tweaking powder, good brass preparation technique and shooting ability will produce the most/best results.

If you are shooting .25-.75 MOA I think there is a lot of room for your shooting to get consistent. You may learn that your long brass has little to no change in your group size if your groups open and close a lot while shooting.


Edit:
Also of note is the particular brass you are using, if you are full length sizing each time (as opposed to just neck sizing).

How much is your brass growing after each firing?
Are you considering annealing?
Are you bumping the shoulder back at all?

I trim down to 2.010" and see about .002-.004" on some of my slower moving loads. This has been consistent with most brass I use, except Lapua, which in my experience grows the least.

 

[Flea21]

" My HS Precision DBM has a max OAL of 2.855 so these are gonna be single shot loads unfortubately but hopefully more accurate than my last ones at 2.800 which were shooting .25-.75 MOA as they sat. "

Are you loading these for benchrest? If it were me, I'd stick with ammo that feeds through the mag. Even if you manage to get your ~0.50 moa down to a ~0.30 moa, you'll have different POA/data for ammo that feeds and ammo that does not. I have a hard enough time keeping up with one bullet / rifle. JMHO. Either way, good shooting.

Thx for the compliment.. I shoot sometimes from a table using a bipod and other times prone, which is my favorite. I shoot consistently the same MOAs in either position. I gotta check how much the brass is stretching, but id just assume let it stretch till it gets close to the max my chamber will allow and trim to .015-.020 shorter than that number at that point and maintain that trim length. This way my brass will last longer cuz I would be trimming less, at least to that point that is. Also, I do anneal and FL resize everytime as well as bump the shoulders back in the process .001-.002 to withing spec.

I like the idea of loading to mag length for better fun shooting and not feeding every round. Actually, 2.800 to 2.855 is a big difference in jump and can only improve things I would assume. Although, Im still gonna load some to just shy of the lands to see the difference as well.

This is more just for fun to appease my curiosity of squeezing every bit out that this rifle has to offer.

 

[JGorski]

Are you using bushing dies? If so, it'll take some time to stretch those cases, my Lapua 308 brass stretches .003" each time I size them with a .334" bushing.

 

[Flea21]

Are you using bushing dies? If so, it'll take some time to stretch those cases, my Lapua 308 brass stretches .003" each time I size them with a .334" bushing.

No, im not using a bushing die. Im using Dillon .308 Winchester Rifle 3 Die Set.

 

[1lnbrdg]

I'd stick to the factory trim-to legnth specifications. I know, there are chambers out there that safely take longer cases but SAAMI specs were put out there for safety purposes. Unless you have a chamber casting and can measure the cut legnth for the neck you could be asking for problems.

 

[Flea21]

Thanx for the input.. ive noticed that my rifle, or me, have been performing very well now with an OAL of 2.825" or so. I try not to be so perfect on that nunber because it can be very timw consuming. But I am annealing after every firing and FL resizing as well.

The longer brass dpesnt seem to have any affect on the performance. However, if I xan reduce the trimming that ultimately prolongs the brass lifespan as my loads are not too hot (43.5grs of IMR4064).

I shoot with a bipod and a sandbag on the end of the stock to stabilize the rifle. I do this mostly off a table and occasionally prone when im on private land with my friend.

The groups are improving though. I havent made it past 2.025" on my brass but those are only on their 4th or 5th firing so far.

 

[shell_guy]

I run 2.240 to the ogive and 3.100 OAL to the tip with 208 amax and that's 0.015 off the lands.

 

[Flea21]

I run 2.240 to the ogive and 3.100 OAL to the tip with 208 amax and that's 0.015 off the lands.

Wow.. Your brass is 2.240"?
How long did that take to stretch to that length and when you get there, how many firings before theyre done!

 

[nnn66]

Flea21: Shell-guy is saying 2.240 to the ogive...not a case length of 2.240. You may need to research the term ogive.

 

[Flea21]

I know what ogive is.. thank you.

 

[nnn66]

Ok, sorry Flea...didn't mean to offend. It's just that your question about brass stretching to 2.240 made me think you weren't familiar with the term ogive, so I figured I'd point that out to you.

 

[Flea21]

Yea I get it.. im just trying to get mt brass stretched out to around 2.040 and trim to around 2.025 or something like that.

 

[sjb269]

I have found the 175 SMKs can take a huge range of jump and COAL with very little variation in accuracy. As a side benefit to loading to SAMMI specs, I like being able to let friends use my reloads if they come up a bit light on ammo during a shooting session. Or if we got in a situation where we needed to use our rifles for other purposes.