Straight Wall Case Trim Question

[Zen Archery]

I'm a novice with straight wall cases and need wisdom from those more experienced. This is for 350 Legend.
A). How much trim (if any) should I allow between case and throat?
My most accurate load has the case hard pressed into throat at 1.705. But that added a lot of pressure. Cycling was also problematic in gas gun. 1.700 was old SAAMI spec. is kissing throat. Accuracy was over 1.25". 1.695 allows room for stretch but accuracy is between 1.10-1.25." With cheap Nosler 9mm Bullets.

B). Do you anneal straight wall cases since they don't have a shoulder?

 

[Dmagna]

I would, it would help with consistent "neck" tension. Help prevent spring back,

 

[ARlife4me]

Without having a rim it should headspace off the mouth. Trimmer is very important. Trim to what book states which is usually no different than every other case, max - .010". With the 1.695 case did you subtract .005 from coal also? What is this in, AR, lever, bolt or something else? If it's an AR then either headspace or chamber is wrong if you can't meet case length trim specs. What does factory ammo chamber like or perform?

 

[Zen Archery]

Yes AR15. This barrel is old. That's why I stated "old SAAMI" I believed they changed it 1.710 in the past year and a half. So I am having to rely on old SAAMI and the reason I ran the bore scope.

Having not loaded a lot straight walls I just need to know if I should have space, touch, or jam the case into the throat.

 

[ARlife4me]

Definitely not jam. What kind of shape is the brass in after firing? I know you stated the pressure is higher, but. In a bad way or still safe? Is there any way to get it throated? Well technically not throated, just lengthen the chamber? I'd try and cut bach the brass to .010 off of what you do have with your headspace. If 1.695 is touching, then do 1.685 or 1.690 if touching is at 1.700. if no it's driving the bolt. Check to gas rings and the carrier for chafing/grooves. Since the case could be an extra 10 to 20 thou shorter than newer design you mi5also subtract that off of book load.

 

[Seabeeken]

i have never known of straightwall cases being annealed. I load 350 for a friends savage rifle. It shoots .5" . The case headspaces on the mouth of the case as does most semi auto pistol cartridges. They do stretch so i would measure them and trim to a consistent length

 

[can1010]

jamming the brass into the throat is basically adding an extremely heavy crimp. if jamming is where the accuracy is just trim to touch and crank up the crimp pressure to bring accuracy back. never annealed straight wall cases but might be something to test but increasing crimp should solve your problem, use the same OAL as the jammed rounds so the bullet jump is the same eliminating one variable at a time.

 

[Seabeeken]

jamming the brass into the throat is basically adding an extremely heavy crimp. if jamming is where the accuracy is just trim to touch and crank up the crimp pressure to bring accuracy back. never annealed straight wall cases but might be something to test but increasing crimp should solve your problem, use the same OAL as the jammed rounds so the bullet jump is the same eliminating one variable at a time.

Jamming brass in the throat is going to raise pressures dramatically. Keep brass in the chamber. Jamming bullets on hunting rifles could lead to a bullet stuck in the bore when an unfired round is extracted. Learned that on a varmint rifle the hard way.

 

[can1010]

Jamming brass in the throat is going to raise pressures dramatically. Keep brass in the chamber. Jamming bullets on hunting rifles could lead to a bullet stuck in the bore when an unfired round is extracted. Learned that on a varmint rifle the hard way.

i agree that is why i said trim case and add crimp pressure. never suggested jamming the bullet just leaving the same so he only changes one variable at a time

 

[Mallardhammer]

Definitely anneal if you're running a crimp, especially if using starline.