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Posted: 8/29/2016 3:58:40 PM EDT
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I recently purchased a Savage Model 10 .308 Winchester and new Lapua Brass. I was trying to fire form the brass and after four firings on the new brass it still is not tight in the chamber.
The brass was obviously not full length sized when I reloaded the rounds. It was neck sized. The brass that was fired four time measures 1.5745" - 1.5750" and the once fired is around 1.5735" - 1.5740". I measured the shoulder length on the brass before and after reloading so I know it is not getting pushed back. It just seems like the brass isn't growing like it should. Any clue as to what can be going on here? |
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I also think I figured out my problem. I'm willing to bet it is a sloppy chamber. The brass grows .010" after one firing and then won't grow anymore no matter how many times it is fired. The brass will only stretch so far before it stops.
I am going to call Savage tomorrow and see what they say. |
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Quoted:
The firing pin strike can set the shoulder back .006" (223). If the powder charge is a starting or mid-range loading, brass may not fully expand. Soon or later, brass will become hard to chamber , when only neck sizing. They are 168gr Sierra Match King bullets of 43.0gr of Reloader 15. They should be plenty hot enough. |
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Quoted:
I also think I figured out my problem. I'm willing to bet it is a sloppy chamber. The brass grows .010" after one firing and then won't grow anymore no matter how many times it is fired. The brass will only stretch so far before it stops. I am going to call Savage tomorrow and see what they say. Let us know what they say. I have a savage in 338 lapua. Chamber is so tight, I have to size shoulder after just one firing. I tried neck sizing only and rounds dont chamber very well. Most chamber with a bit of force. A couple out of last 100 didnt chamber at all. |
 1.640" maximum SAAMI chamber, head to datum. http://www.saami.org/PubResources/CC_Drawings/Rifle/308%20Winchester.pdf Check Alliant data. 45 gr is maximum for a Speer 168 gr and also a ( 180 gr misprint??) If your accuracy is good, no reason to up the powder charge. The comparator will not match SAAMI head to datum measurement most times. I think your worried about nothing.  |
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It sounds like what is happening is exactly what SHOULD be happening when you have the right load and are doing everything right.
The factory new brass will always be short to make sure it fits every gun chambered for that caliber. As you found out your brand is .010'' short and grows that much to fill your chamber on the first firing. Brass was chosen for cartridges because of its' properties and abilities. It's strong yet pliable enough to be formed in a die, it expands to grip the chamber walls then contracts a small amount for easy extraction, and it's relatively inexpensive compared to other materials that may be used. You're doing good by getting 4 firings and not having to FL resize yet. I just started neck sizing and have only 2 on my brass so far but I hope to get a lot more like I've read about. I hear some guys get as many as 10-12 firings before they have to resize. That would be great for longer brass life. Like the guy above said, you are worried about nothing. Be happy you don't have to resize very often. |
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Quoted:
It sounds like what is happening is exactly what SHOULD be happening when you have the right load and are doing everything right. The factory new brass will always be short to make sure it fits every gun chambered for that caliber. As you found out your brand is .010'' short and grows that much to fill your chamber on the first firing. Brass was chosen for cartridges because of its' properties and abilities. It's strong yet pliable enough to be formed in a die, it expands to grip the chamber walls then contracts a small amount for easy extraction, and it's relatively inexpensive compared to other materials that may be used. You're doing good by getting 4 firings and not having to FL resize yet. I just started neck sizing and have only 2 on my brass so far but I hope to get a lot more like I've read about. I hear some guys get as many as 10-12 firings before they have to resize. That would be great for longer brass life. Like the guy above said, you are worried about nothing. Be happy you don't have to resize very often. When you talk about the brass growing .010" to fill my chamber, you're forgetting to realize that it actually isn't filling the chamber. That is why it is not tight after the second, third, or forth firing. The brass doesn't grow anymore after the first firing. It can only grow so much. Problem is the chamber is too big and the free bore is too much. I can't seat bullet into the lands because they won't reach the case. I called Savage and they seem to agree that the chamber is out of spec. They sent me a call tag number to send the rifle back. |
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Neck sizing it just that, and you should not be bumping the shoulder at all.
To set the die up correctly, sharpie pen mark one of the case necks, and only lower the die down so the neck sizing stops just short of the shoulder isntead. Hence this is all you are going for, with just a hint of the neck not sized down just before the shoulder. 
As for fire forming, try to do with with the same working pressures as the load. Hence reduced loads are only use to blow the case out to the chamber isntead, such as in the case where the sizer will not get the shape of the round correctly to be with, and you need initial reduced loads to first blow the case out to the chamber shape ( think ackly improved.where the new sizer may not get you all the way there from the base case is started out as with the shoulder angle), then once blow out to the shoulder shape, neck sizing of the case with full loads to fire form to the chamber next. (reduced loads ends up with too much case spring back when first blowing the case out to the sharp of the chamber shoulder, so this is why you have to do the second full load charge to get the case to fire form to the chamber correctly as well). So being that this a 308 chamber first firing of the fully sized case should have fire formed the case, then cases cleaned and only neck sized as show above, a quick check to verify that the case OAL is still good, and they they get loaded as your final fire formed case loads (with a .003" jump to lands) as your working your charge ladder to get the rifle/barrel to sing. Also, when fire forming, do so with about 150 rounds ,then just keep 100 of the case in rotation, and the extra 50 as needed for when the cases in the first 100 start to fail (primer pockets get too loose). Hence on your final loads once dialed via ladder work ups, only 100 rounds all loaded, all them shoot , and before you load then the next time as a batch, double check your jump to throat plasma erosion, and adjust your OAL to maintain the .003" jump to lands. If you think that you are going to shoot more than 100 round per event, then you can work a second one rounds into the mix, but keep in mind that you may not be compensating for plasma throat erosion for 200 rounds at a time isntead. As for a load start point, 168HPBT match bullet, 40.6gr of 4064, Federal 215M, and make sure to take the time to final trickle the power to make sure your on the mark each case powder fill, and that you have fully prepped and unified the brass. This load is going to sleep fast, will find one of the first still end of harmonic muzzle entry point somewhere around it, and will work for a good short range load. From there, you can start working up from that found sweet spot on a longer range load to hit one of the muzzle harmonic end point exists, and that may not sleep for several hundred yards for a effective 800yard load. Note, on the the long range load, the barrel has opposing still end points in its oblong movement as norma, and when you find one of these still end point with the power weight/bullet speed, the barrel is going to print its tightest at the longer range (faster the bullet is pushed, the longer it needs in range to sleep). as as your working up the ladder, will find these along the way, and it just a mater of if you can find the other side , before you max out on working pressure for your long range loads isntead. So muzzle is moving like this in a oblong pattern, 
And it at the oblong ends of the movement (stillest point in the movement of the barrel) that you are trying to get the bullet exit isntead. If you are working from your short range load and find the correct amount of powder to have the bullet exit from say the crest, then it will be the trough that you are trying to find for your exit point for your faster loads instead (and move the target out far enough that the faster bullet has enough time to sleep before it reaches the target. If you working on 600 yard load, the bullet will not have slept until say the 300 yard mark so don't do testing with the target at say less than 400 yard instead If you are pushing 1K, then want to start with the Palma 155 match bullets , that is able to stay super sonic out past the 1K mark isntead. Hence with a 168gr bullet in a 308, around the 800 yard mark is where the bullet goes from super sonic to sub sonic, and when the pressure wave moves from behind the bullet and starts to over take it back in from the tip, these cause the bullet to come out sleep, and all bets are off where it will end up instead. |
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The brass will fire form the first time with a full load to blow all the way out to match the chamber.
The low pressure loads are used when you are making the brass from another type of case or changing the shoulder angle, and in process the case has not been fully shaped to the chamber wall shape by the sizer isntead. To understand this, take a look at the difference between a standard 30-30, and a 30-30 ackley improved case. 
So to back it up, your brass is being fire form to the chamber will the full loads to begin with, and it the way you are neck sizing that causing the problem instead. Again, with a neck sizer dies, you are only sizing the neck of the case back down and have to stop before any of the shoulder of the case has been change instead. So, as you are depriming and neck sizing only, adjust the die down slowly, and stop adjusting it down once only the neck has been sized just short of the start point of the shoulder. Again, it only the neck just short of the start point of the shoulders that is being sized back down, and the shoulders and below of the case are not touched instead.
If you want to bump the shoulder back, then this is down with a full length resizer, and the dies is adjusted down to just lightly bump the shoulders back isntead. Hence shoulder first mic from a spent case, and them the sizer well off the shell holder is adjusted downwards until the shoulders are just bumped back the desired amounts. And yes shoulder bump has to be done with a full sizer, since a neck only sizer will not have the needed suport to the case to bump the shoulders back isntead. |
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