.308 OAL Question

[JFTFI2]

Savage 10FCP
24"
RH 1:10"
175 SMK
Win. cases

Determined OAL to be 2.729 just touching rifling. 2.305 to ogive. I have been shooting SW ammo 175 Match with no problems. OAL on factory ammo is 2.807. Does this mean that the factory ammo is 0.078 jammed? I am new at this. Help

 

[cav.scout]

Re: .308 OAL Question

I have a savage 10 fcp-sr same short throat. I've had no issues shooting rounds with longer oal, but yes you are in the rifling.

 

[JFTFI2]

Re: .308 OAL Question

Thanks for the info. I want to start working up some loads starting with about a.010 jam and was a little confused with what I was seeing.

 

[VKC]

Re: .308 OAL Question

Seems like a short chamber for a factory 308win.

 

[cav.scout]

Re: .308 OAL Question

I called Savage told them what I was seeing they said it was GTG. So I'd it blows up I guess I'll own Savage Arms. Lol

 

[JFTFI2]

Re: .308 OAL Question

I called Savage this morning to get the factory measurment. After about 10 min. I was told they did not release that info. I also talked with someone with Hodgdon about there loading data for a 175 GR SIE HPBT using Varget compared to the Sierra reloading manual. He said that Sierra does not use pressure barrels when developing there load data. How weird is that. Hodgdon uses the following pressure barrel for the .308 Win. The over all case length on my rifle chamber is 2.0415 using a Wilson insert.

24"
1:12"
Win. case
210M primer
Trim length is 2.005

 

[Deadshot2]

Re: .308 OAL Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vkc</div><div class="ubbcode-body">Seems like a short chamber for a factory 308win. </div></div>

Same thought here. But whatever works, right?

As for factory ammo being "jammed", it's going to depend on the profile of the bullet. Some have a shorter base to ogive measurement which means that the bullet, when chambered, will actually be a ways off the rifling. A round nose bullet with the ogive closer to the meplat/tip will more likely jam at factory length.

 

[DubGunner]

Re: .308 OAL Question

Measured about the same on my straight-from-the-factory FCP. Factory Fed Match feels a little snug on some rounds, but shoots great every single time. I load a little shorter than the factory stuff, I believe it's 2.768 for me.

 

[Greg Langelius *]

Re: .308 OAL Question

This sound like my own experience with several 10FP .308's over the years.

I'd normally consider this as a possible issue, except I've never seen or heard of any significant problems/issues developing from the situation.

I'm not going to throw any flags on this.

Logically, a shorter throat could have positive bore/throat life implications.

Beyond that, I choose to make no further conjecture.

Greg

 

[JFTFI2]

Re: .308 OAL Question

Finally got my Sinclair seating tool that has been backordered for about 9 weeks. Using this tool I am showing 2.780 (OAL)to the lands. The first method I used was the one discribed in another post on this site. It uses a cleaning rod with stops. Tried it again with the same short results. The best I can determine is for some reason a bullet seated long is not reaching the lands. When you use the Sinclair tool the bullet is dropped in and stops on the lands. Just shows how using the right tool gives you the right results. Thanks for the response.

 

[cav.scout]

Re: .308 OAL Question

As I said before I have the same short throat on my Savage. Now you gotta wonder seating the bullet in further increases pressure and so does jamming it in the lands. It would be nice to know the difference between the two.

 

[JFTFI2]

Re: .308 OAL Question

As I understand it is important to have the bullet jammed approx. .010 when working on load development. I have used a bullet comparator on a dummy round seated to 2.780 (OAL) to get a measurement to the ogive and added the .010 to make sure that I am fully seated. Pressures are suppose to decrease when you work on jump lenghts. Have never seen data on increasing jam.

 

[cav.scout]

Re: .308 OAL Question

No what I'm saying is the further you seat the bullet in the case it will increase the pressure. Also if the bullets were left at SAMMI length they would be jammed in the lands which also would increase pressure. It would just be interesting to know which one causes higher pressure that's all. I just don't like seating my bullets that far in especially if it's a heavy powder charge and your using a 175 Your going to compress the hell out of that's load. On the other hand if it's a light load the seating depth may help velocity out. Idk too many variables just a thought though.

 

[JFTFI2]

Re: .308 OAL Question

I see what you are saying. Thanks for the input.

 

[oldfatguy]

Re: .308 OAL Question

OAL is important if loading to feed from your magazine. However the OAL, base to meplat/tip length, is only related to the base to ogive distance. The distance from the ogive to the extream tip of the bullet just is not very consistant which is why meplat uniforming tools are bought and used.

The base to ogive measurement is what really tells you how far off or into the lands your bullet is.

OFG

 

[BIRDHUNTER]

Re: .308 OAL Question

One of your measurements is off? 2.305 off the Ogive is way out there and does not equal 2.729 OAL for a 308 w/175 SMK. 2.252 Ogive is what I use and that equates to 2.838 OAL +/-. If you are shooting SWA ammo and you don't feel any pressure closing the bolt you are not touching the lands. To make sure color the tip of one of SWA's rounds and chamber it and then remove it. If the round does not show any signs of the lands on it your not touching.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JFTFI2</div><div class="ubbcode-body">Savage 10FCP
24"
RH 1:10"
175 SMK
Win. cases

Determined OAL to be 2.729 just touching rifling. 2.305 to ogive. I have been shooting SW ammo 175 Match with no problems. OAL on factory ammo is 2.807. Does this mean that the factory ammo is 0.078 jammed? I am new at this. Help </div></div>

 

[learjet]

Re: .308 OAL Question

gotta agree w birdhunter. something fishy w ur measurements

if we subtract ur ogive length from your OAL the difference is only .424. SMKs are longer than that fwd of the ogive.

bhs' would be 2.838-2.252=.586
mines 2.800ish - 2.135= .665

these r close enough for me to accept the difference, most likely from the tool used to measure the ogive length. small variances in the diameter of the hole in the tool that rests at the ogive will give relatively large differences in measured length. urs seems real long. what are u using to measure to the ogive?

 

[Texar2]

Re: .308 OAL Question

Does the tool take into account that the bolt face is recessed and the case does not go all the way into the barrel? If it shoots fine with no pressure signs then fire a few thousand rounds through it then run a throating tool in there and clean it up. Then you will be gtg again. 175gr smk are not very picky about distance to lands. Load up some varget and go shoot.