Weird pressures with cfe 223

[Bvin91]

Hi, I'm fairly new to reloading so I'm hoping to get some advice from more seasoned vets.
I recently got some cfe 223 for use in some .308 loads with some 175gr Sierra matchkings.
According to the hodgdon website starting load is 45.5 gr and max load is 47.5, so I loaded 25 rounds (5 groups of 5) starting with 5 at 45.9 gr and increasing .3 grains all the way up to 47.1

I also ran these loads through quickload with correct case measurements and capacity to help verify the loads were safe.

I got out to the range this past weekend and started with a 45.9gr round and it was WAY over pressure. The concussion and recoil was noticeably heavier and the bullet chrono'd at 2750. When I checked the brass, the primer was almost blown out of the case and the the firing pin indent was an outdent.

I always hand weigh charges and I have pulled the other 4 from that group to verify the charges were correct, and they were.

Quickload says that to push 175 smk's 2750 means I had a chamber pressure around 68,000

Did I screw up somewhere? I've never had this kind of discrepancy from published load data before.

Any help is appreciated.

 

[troy fairweather]

Sometime guns just have a lower max load, make sure the throat area is not carboned up. What temps were you shooting in or did the ammo get hot. Some pictures of the brass would be nice, gun info may help how did you get your case volume?. Is there a service round load for the powder.

There are other things to check I just can't think right now, is the firing pin hole how it should be, 100% on the headspace. To much neck tension can get higher pressure, even not using the exact primer you could have a lower max load. Was the bolt lift heavy?

Welcome to thr.

 

[BigBore44]

When you say you hand weigh the charges, do you mean on a digital scale or on a pendulum? How much crimp are you putting on those bullets? And....pretty much all the questions @troy fairweather asked.

 

[Bvin91]

Gun is a DPMS pattern ar-10 with a 20" faxon match barrel and brownells bolt and carrier. I fired a couple rounds of factory Aguila to verify zero before the handload in question. Gun was thoroughly cleaned beforehand and is fairly new (~200 rounds down the pipe). I did substitute Winchester primers for the listed Federal. I didn't crimp after seating.

 

[Bvin91]

Brass in question

 

[troy fairweather]

We're did the brass land on the hot round. Plus I believe wlr primers are sometimes considered the same as magnum primers.

 

[Bvin91]

View attachment 995141 When you say you hand weigh the charges, do you mean on a digital scale or on a pendulum? How much crimp are you putting on those bullets? And....pretty much all the questions @troy fairweather asked.

Weighed on a digital scale that's never given me problems and is calibrated before each use.

 

[troy fairweather]

That brass looks fine to me, firing pin hole maybe out of spec or the pin

 

[Bvin91]

We're did the brass land on the hot round. Plus I believe wlr primers are sometimes considered the same as magnum primers.

I had a brass catcher up so there was no way for me to determine.

 

[troy fairweather]

The weeb area on the brass looks fine, if pressure was to high that will be know out some. Would be about 1-2 thou larger about a 1/8" above the extractor cut any more and pressure I high on primer pocket will loosen .

 

[troy fairweather]

Maybe a picture of your bolt face, push it in so the firing pin is sticking out.

 

[Bvin91]

Maybe a picture of your bolt face, push it in so the firing pin is sticking out.

Sure.

 

[Bvin91]

The weeb area on the brass looks fine, if pressure was to high that will be know out some. Would be about 1-2 thou larger about a 1/8" above the extractor cut any more and pressure I high on primer pocket will loosen .

So am I making a bigger deal out of the inverted firing pin indent than it really is?

 

[BigBore44]

Weighed on a digital scale that's never given me problems and is calibrated before each use.

Ok I’m not trying to question your reloading but there are things that people do sometimes that they don’t think about. And they make a difference. One is not changing batteries in their scales. Another is placing the scale on something soft. I always weigh each charge on a pendulum with a trickle charger. Oh, what was your COAL? Bullet setback could absolutely cause it. You said you used the right case measurements but didn’t mention cartridge length.

 

[troy fairweather]

Well that primer flow like that is not good, it can cause many problems. I'd try a magnum primer I think federal and cci have the thickest cups.

 

[troy fairweather]

Be sure the brass length is were it should, about ten thousand under max is good.to add what bigbore 44 said make sure the scale is perfectly level, and no fan/ac even a tv or radio can mess with them.

 

[Bvin91]

Ok I’m not trying to question your reloading but there are things that people do sometimes that they don’t think about. And they make a difference. One is not changing batteries in their scales. Another is placing the scale on something soft. I always weigh each charge on a pendulum with a trickle charger. Oh, what was your COAL? Bullet setback could absolutely cause it. You said you used the right case measurements but didn’t mention cartridge length.

2.815" which I understand can raise pressure, but I ran it all through quickload which said the extra 15 thousandths should only add a couple hundred psi.

And yeah I know there's definitely (and probably likely) some user error that could be the cause, I guess that's why I'm here to try and rule out any external factors that I'm missing. Like I said, I am still pretty new to this so I don't claim to be even close to an expert.

 

[Bvin91]

Be sure the brass length is were it should, about ten thousand under max is good.to add what bigbore 44 said make sure the scale is perfectly level, and no fan/ac even a tv or radio can mess with them.

Brass was a hair short at 2.0045" and yeah the scale always stays on a hard flat table in a room with no electronics besides my phone, so if there was an overcharge it would be most likely be on me.

 

[Bvin91]

Well that primer flow like that is not good, it can cause many problems. I'd try a magnum primer I think federal and cci have the thickest cups.

Maybe I'll just back my charge off by a grain or so and work up from there. The Winchester primers are all I have right now for large rifle, and considering the primer situation it may be a while before I have the chance to switch over to something else.

 

[troy fairweather]

Qd goes of a sammi spec chamber, but really all chambers are different. Have you check how fare off the bullet is from the lands and groves.

 

[Bvin91]

Qd goes of a sammi spec chamber, but really all chambers are different. Have you check how fare off the bullet is from the lands and groves.

Yes, although crudely. I just used a fired case with the neck dimpled on one side to lightly hold a bullet in place then marked the bullet and then measured the oal afterwards.
I got a measurement ~2.830"
I've been meaning to get some proper tools for some more exact measurements.

 

[edwardware]

So am I making a bigger deal out of the inverted firing pin indent than it really is?

Yes, that brass case does not indicate high pressure. On the contrary, the primer radius looks just fine.

The rim around the indentation indicates a slightly oversized FP hole, or soft primer cup. Not a big problem unless it ties up the gun or pierces primers.

 

[243winxb]

Adjustable gas block? Try less gas. Try to keep the fired case in the chamber longer. If the firing pin stays in contact with the primer longer, there may be less primer flow?

Gas gun don't always run at the same pressures as a bolt gun. Port pressure is different between powder burn rates. Port pressure is what cycles the action.

 

[Bfh_auto]

Brass was a hair short at 2.0045" and yeah the scale always stays on a hard flat table in a room with no electronics besides my phone, so if there was an overcharge it would be most likely be on me.

Your phone can cause inaccurate readings. But I doubt it or over pressure is the cause of your inverted primers.
There are better guys than me for that info.

 

[Bvin91]

Adjustable gas block? Try less gas.

Yes and it was significantly over gassed. I had no way to adjust it at the range due to leaving some tools at home. I've got it down now, so hopefully that will help.