Long chamber

[cramer]

I posted a while back about some issues I was having with my .308. While toying with seating depth I ran an empty case and bullet in the rifle to determine the actual length of my chamber and when I pulled it out it measured 2.9660"!!!! SAAMI is 2.810" I believe...... I don't know if it is a headspace issue or chamber/throat issue, either way I don't feel like wasting components trying for accuracy until it's figured out. Any tips?


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[Wyo7200]

Is it a Remington?

 

[bboswell]

Pretty typical for Remington at least. Don't give up though, I was able to get sub 1/2 MOA loads for my 308 that fit in my Wyatts extends box magazine.

Even with the extended box they jump a long ways but they shoot

 

[elkeater2]

I'm going to get a reputation if I keep it up, but will risk saying it again. Chamber cast! I see so many struggle with chambers, throats, alignment, concentricity, etc. When I had doubts or similar problems, making a cast always gave me peace of mind and helped me figure out what to do next. I went through a pile of components messing with things I didn't need to.
EE2

 

[cramer]

No it's a home build using a McGowan barrel. My mind got ahead of itself, I realize that it's not a headspace issue. As much as I hate to ask........how do I make a cast? And how will it tell me what to look at load wise?


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[cramer]

I did make up some test loads with a COAL length of 2.930" that cut my group size down to 1"@100. That's a vast improvement from before, but even using that as a starting point turns my bolt gun into a 2 shot due to mag well sizing.


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[Guy Miner]

It's not uncommon to cut off a few threads and "set back" the barrel.

 

[BillPa]

As much as I hate to ask........how do I make a cast? And how will it tell me what to look at load wise?

I make chamber casts using Cerosafe. http://www.brownells.com/gunsmith-t.../cerrosafe-chamber-casting-alloy-prod384.aspx
They're not difficult to make but will require some practice to turn out reasonably good ones.

This is one I made of a new 25-06 barrel last fall. From the end of the neck portion of the chamber to the lands is the length of the freebore. Its mirror image of the chamber so the lands are the grooves you see in bore portion of the cast.
Unfortunately they won't tell you much if anything about the seating depths. You'll need to use one of the many methods available to find that length for the bullet or bullets you're using.

Bill

 

[muleman]

Many guns shoot very well with a significant jump to the lands. Most guns have several different accuracy nodes that will work for you. Start with mag length loads and find the most accurate powder and charge weight. Then work backwards in OAL to find the best node. Sometimes it's easy and sometimes you'll burn some powder. In the 5 or 6 dozen rifles I've loaded for I've only had one that wouldn't shoot.

Good Luck,

Scott

 

[SJB358]

Many guns shoot very well with a significant jump to the lands. Most guns have several different accuracy nodes that will work for you. Start with mag length loads and find the most accurate powder and charge weight. Then work backwards in OAL to find the best node. Sometimes it's easy and sometimes you'll burn some powder. In the 5 or 6 dozen rifles I've loaded for I've only had one that wouldn't shoot.

Good Luck,

Scott

I'm with Scott here. Try it out with a few Bullets at mag length. It might surprise you.


If you don't like it, like Guy said, set it back and rechamber it.

 

[Whitesheep]

+1 on BillPa's recommendation for a chamber cast. Cerosafe works great. Use a dowel with a patch on the end to block the barrel ahead of the chamber a sufficient amount and fill the chamber with Cerosafe. I simply melt it in a bullet casting ladle with a propane torch and pour it in. Cerosafe has a very low melting temperature and is made just for this purpose. Check out Midway's video here for how it is done: https://www.youtube.com/watch?v=2d5DA4_OcuE

Chamber casting has helped me rule out chamber problems in a couple of rifles.

 

[Yoda]

Cramer is this a savage ? Like in barrel nut ?

 

[HTDUCK]

My Rem 700 308 has .250 freebore in it and it shoots very well with 175 SMKs and 45 grs of Varget.
Hunting load is 46 grs Varget and a 165 NBT.
Both are sub moa at 200

 

[kraky1]

I had a Weatherby ultralight that drove me crazy years ago.... I was bound and determined to find a good load at magazine length which still had a pretty significant jump to the lands because of weatherby free bore. I tried just about every hunting bullet and powder combination out there and could not find a load that didn't stink. I finally set the bullets really deep like Factory ammo and the gun started shooting like a house afire. A lot of Remington's have the same situation. Start loading and see what it does!

 

[Polaris]

What bullets are you using? Bullets have different ogives and one that will be too long for the magazine when run out may have an equal weight counterpart that will come closer.

Also don't get too hung up on theoretical accuracy problems before you burn any powder.

My 6.5 Swedish military rifle was originally designed for a 160 gr Cu/Ni roundnose. Talk about a long throat. That one will print near MOA with issue iron sights and a 123 Nosler CC that is FAR off the lands. No doubt it would be sub-MOA with optics.

 

[cramer]

Cramer is this a savage ? Like in barrel nut ?

It has a barrel nut but it's actually a Marlin XS7 action. McGowen 1:10 SS sporter.....

 

[cramer]

What bullets are you using? Bullets have different ogives and one that will be too long for the magazine when run out may have an equal weight counterpart that will come closer.

Also don't get too hung up on theoretical accuracy problems before you burn any powder.

My 6.5 Swedish military rifle was originally designed for a 160 gr Cu/Ni roundnose. Talk about a long throat. That one will print near MOA with issue iron sights and a 123 Nosler CC that is FAR off the lands. No doubt it would be sub-MOA with optics.

ive been trying 150 gr SSTs but I just picked up a test pack of 180 gr Accubonds to play with. The Accubonds with 42 gr of 4064 with a COAL of 2.925 shoot better than anything has so far, but I only tried one batch.

 

[cramer]

I made up some loads with a COAL of 2.80", that's the longest that still allows me to load more than one at a time. Started with 38 gr of 4064 and worked up to 45 gr. All shot off of a bench using a sled. Best group was 1.11" outside to outside........any suggestions?

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[truck driver]

I would shoot #39 again and if it repeats play around with seating depth .

 

[HeathSexton]

39 and seat them deeper by .005" at a time