Im getting shoulder dents after firing. Im shooting an AR-10 308 Win using hornady 160gr FTX with IMR 4320 33.9gr seating at .035 under ogive.????

[ARlife4me]

#1 You are 10 grains under on the powder.

#2 Seating using the ogive as a guide is NOT good reloading practises. COL is. Generally 308 win falls between 2.750 and 2.800. But look up the SAAMI specs to find out the min and max

The overall length (OAL) of an ammunition cartridge is a measurement from the base of the brass shell casing to the tip of the bullet, seated into the brass casing. Cartridge overall length, or "COL", is important to safe functioning of reloads in firearms.

coal is dependent on bullet weight and throat (if custom). 110's @ 2.515" in 308win

 

[budlight]

coal is dependent on bullet weight and throat (if custom). 110's @ 2.515" in 308win

who would shoot 110's out of 308? :lol That is why I said look up the SAAMI min and max. The correct COL for AR platforms is length limited by the magazine. I have some .300 longer throated custom barrels for bolt rifles which turned them into single shots (For Target shooting) rather impractical for AR's

 

[ARlife4me]

who would shoot 110's out of 308? :lol That is why I said look up the SAAMI min and max. The correct COL for AR platforms is length limited by the magazine. I have some .300 longer throated custom barrels for bolt rifles which turned them into single shots (For Target shooting) rather impractical for AR's

some like to have fun (ie, me) as i'll shoot lots on fmj's from 110-185's in barrel lengths from 12.5-26". kinda like shooting 123's in a 300wm for speed. little difficult to get an ar mag going 3.100" for sure! i also shoot 90gr .355 in 357sig as most shoot 124/5-147's. not my cup of tea! sbr w/147's would be more like my style. when my 243win ar barrel was chambered (don't recall by which company) didn't get the saami memo as it is nearing .030" short.

 

[xsn10s]

49th Edition Lyman manual list IMR 4320. But I do believe you're right he's below charge weight for the powder being used.
Edit Hornady 11th Edition list 33.9 as start for 165-168 gr. Not in service rifle though. I am new to reloading myself. And is there much of a difference between the two in powder usage ? Other than possibly the dwell time. And needing a thicker cup primer. I would think increasing his charge slightly should solve his issue ?

I've never been in powder manufacturing so I cannot say with any degree of conviction what the chemical differences are. I don't think primers cup thickness is a cause for the dents. The double spike I'm talking about is he's not getting enough pressure to seal the case mouth and neck in the chamber when firing. So the gases escape and seal at the body shoulder junction thus collapsing/ denting the shoulder. Raising the charge to listed starting charges should help. Going below suggested charge weight can create a dangerous over pressure situation from what I've read.

 

[ARlife4me]

I've never been in powder manufacturing so I cannot say with any degree of conviction what the chemical differences are. I don't think primers cup thickness is a cause for the dents. The double spike I'm talking about is he's not getting enough pressure to seal the case mouth and neck in the chamber when firing. So the gases escape and seal at the body shoulder junction thus collapsing/ denting the shoulder. Raising the charge to listed starting charges should help. Going below suggested charge weight can create a dangerous over pressure situation from what I've read.

not just a low pressure possibility, but low case fill could cause that also depending on burn rate.

question for the op, did the bullet exit the muzzle? seems like the bolt would unlock early on a double spike. of course, if it happened at the gas port, but then the bolt would cycle like it was op'd.

 

[M1A1ABRAMS]

I've never been in powder manufacturing so I cannot say with any degree of conviction what the chemical differences are. I don't think primers cup thickness is a cause for the dents. The double spike I'm talking about is he's not getting enough pressure to seal the case mouth and neck in the chamber when firing. So the gases escape and seal at the body shoulder junction thus collapsing/ denting the shoulder. Raising the charge to listed starting charges should help. Going below suggested charge weight can create a dangerous over pressure situation from what I've read.

I know the primers have nothing to do with his issue. I was just stating another difference between a service rifle & other rifles when reloading. The charge he used was in Hornady 11 th edition starting charge weight as I mentioned before. But it was not in the service rifle section. And Lyman list the charge as higher but don't look to differentiate from a service rifle.

 

[xsn10s]

I know the primers have nothing to do with his issue. I was just stating another difference between a service rifle & other rifles when reloading. The charge he used was in Hornady 11 th edition starting charge weight as I mentioned before. But it was not in the service rifle section. And Lyman list the charge as higher but don't look to differentiate from a service rifle.

I had already mentioned that IMR 4320 wasn't listed in the service rifle loads on Hodgdon's website. In any case the OP hasn't been active so I'll let him do whatever he's going to do.

 

[M1A1ABRAMS]

I had already mentioned that IMR 4320 wasn't listed in the service rifle loads on Hodgdon's website. In any case the OP hasn't been active so I'll let him do whatever he's going to do.

I was trying to get a clarification for myself on this topic. And was going by books I have in hand. Thanks anyways.

 

[ARlife4me]

I was trying to get a clarification for myself on this topic. And was going by books I have in hand. Thanks anyways.

i kept looking for 4350 instead of 4320 imr......my bad

 

[M1A1ABRAMS]

deleted

 

[M1A1ABRAMS]

i kept looking for 4350 instead of 4320 imr......my bad

The Lyman 49th edition starts you off at 42 gr of IMR 4320 where as the Hornady list it at 39,3 gr Start load. Neither really list his specific bullet choice. From what I gathered his bullet the FTX was designed more for a lever gun & pistols. Which looked to me like his choice was for a 30-30 Win. Being in the 160 gr. I know you can use components in different usages. But being new I try to stick with known loads for now.

 

[xsn10s]

I was trying to get a clarification for myself on this topic. And was going by books I have in hand. Thanks anyways.

Have you gone to Hodgdon's online data reloading source? That's where I got the load data. It's a great resource and they list IMR powders. Hodgdon acquired IMR in 2003 so I use them as the leading source of load data when dealing with IMR powders. https://hodgdonreloading.com/rldc/

 

[xsn10s]

Also if you have short barreled rifles in the 16" range you can see if they have your cartridge load data in the "pistol" section. Say a 16" 308 Win they have that in there with a 15" barrel.

 

[cajun]

Put some mole skin on the deflector.