Even Factory ammo can be over pressure!

[comen]

Sorry for a long post, but:
I reload for my brother's custom 338 win. This rifle is built on a model 1917, and has been rebored from the original 30-06 to .338, chambered to 338 win mag and cut rifled in 8 groove. The bolt face is appropriately opened and feed rails modified. This gun was purchased at a local pawn shop so we don't know who did the work. In the process of load development I chronographed Federal 225 gr fusion factory loads. I averaged 2996 for five shots, (including 1 at 3016) and 4 of the five showed primer cratering. Rather than decide that these were really awesome factory load speeds, I came to the conclusion that in this rifle, they were way over pressure. The handload I eventually developed shoots a 225 gr A-Frame at 2750 fps with 64.7 grains of 4955. My thought is just because it's a factory load does not mean that the load is safe in your rifle. Has anyone else experienced unusually high velocities and pressure signs in factory loads, especially in custom barrels?

 

[dfanonymous]

I've had some really bad sticky bolts some years ago with Hornady superformance factory ammo for a .300 Win Mag.

 

[MagnumManiac]

My 338's (3) run a 225 Partition right around 3000fps from 26" barrels with RL19...so it's doable but I don't run them at that speed.
I run mine @ 2900fps with either the Partition or Accubonds, the brass likes it there too.

Cheers.

 

[comen]

My 338's (3) run a 225 Partition right around 3000fps from 26" barrels with RL19...so it's doable but I don't run them at that speed.
I run mine @ 2900fps with either the Partition or Accubonds, the brass likes it there too.

Cheers.

Every barrel is different! The charge I'm shooting under the A-frame is the same as Hodgdon shows as a starting charge under the 225 Hornady, at 2562 FPS. The A-Frame may get higher pressures and velocities due to its design, but I have to believe the barrel is part of the equation. Generally, don't higher velocities come from higher pressures, indicating this barrel shows higher pressure for a given powder charge?

 

[MagnumManiac]

I have a pressure trace that I use when developing loads and I have enough factory and custom barrels to know that it's just not pressure equals velocity.
Groove width and number make a difference on speed with the SAME pressure.
For example, my 4 groove 300WM is roughly 100fps faster than my 6 groove barrel at the SAME pressure.
I used to believe x amount of pressure produced y amount of velocity across all barrels...it ain't that simple.

Yes, custom barrels and chambers CAN produce higher pressure because they are tighter in tolerance.

I can't run max book loads in my 264WM due to it being tight in the bore, which is how I ordered it, and I also used a minimum match chamber reamer. I save on powder anyway doing this, takes less to get the same pressure and velocity is way up there too. 29" barrel helps a lot as well. Lol.
I bet I couldn't run factory ammo in this rifle.

Cheers.

 

[comen]

That makes sense to me! Thanks.

 

[L.Sherm]

I've had some really bad sticky bolts some years ago with Hornady superformance factory ammo for a .300 Win Mag.

Your not the only one!

 

[Steves1911]

My cousin had some strange headstamped 308 that caused heavy bolt lift in his savage bolt action. Believe it was mkm headstamp loaded with 150gr softpoints. Looked like someting freedom munitions would sell as "factory reload"

 

[shortmagshooter]

Worst I ever saw was winchester 300 short mag factory loads. Primers were so flat you couldn't make out the separation. Buddy of mine gave me a partial box of silver tips way over pressure in his rem700 so my daughter had a new tikka and I thought what the hell I can start breaking it in with it. You could hardly open the bolt and the primer had became part of the case head.

 

[Ckleeves]

Some of the WSM offerings from Federal are pretty spicy. Both 270 and 300. The brass and the chrono both show it's plenty warm.

 

[Mike Matteson]

I am shooting a 338 WM 200gr ABond @ 3230fps not problems, with W760 powder and Fed 210 primers. No problem. Groups under 1/2" @ 100yds.

 

[muledeer01]

Brother in law purchased Federal 180 gr. For his 300 wsm, he fired a box accuracy was terrible, he showed me the empties into,d him to quit shooting them . Contacted Federal they sent me a return label, heard fro them several weeks later, ammo was over pressure, refunded him money back for them.

 

[ofbandg]

I had a box of 250 grain .338 Win from Federal that produced velocities I have never been able to match safely with handholds. They pressure signs weren't severe but noticeable. I even had friends try a couple in their rifles and they found the same thing.

 

[fishingstockwell]

I have a custom 30 Nosler that I have to load below minimum starting loads and get max load velocity. I tried shooting factory Nosler ammunition and actually blew primers. Chamber was cut with a minimum Sami spec reamer, which may or may not be the issue.