Need help way way over pressure on near minimum powder

[AZlongrangehunting]

If a leading model is the brass doesn't have enough capacity I could try to load this same load in different brass... I'd rather not keep beating the bajesus out of the extractor pin and spring that I'll be replacing after this maybe just get a new bolt head while I'm at it

 

[therifleman556]

Have any/many of your cases had black or sooty necks? If they have that would point to a carboned up chamber/neck area like mentioned above.

 

[AZlongrangehunting]

Well.... I could be doing this wrong with a primitive style of measuring I know you can be off a couple thousandths with a vernier caliper on ID and I do have all the precision measurement tools from engine building but the rifling would stop me from getting groove readings... this is in the groove not on the rifling...

 

[MarkA]

Well.... I could be doing this wrong with a primitive style of measuring I know you can be off a couple thousandths with a vernier caliper on ID and I do have all the precision measurement tools from engine building but the rifling would stop me from getting groove readings... this is in the groove not on the rifling...

Should be near or bit over .284!!!!

Relooking the pic you need to stay out on the narrow tips of calipers and barely touch grooves making sure your not on a rifling.

 

[therifleman556]

Better slug it if there's any question. Your're certain you weren't on the lands at all? That would be almost right for bore diameter.

 

[RockyMtnMT]

Bullets look like etip. I don't see 175g 7mm etip.

 

[RockyMtnMT]

I think I'm mistaken. Must be ablr's.

 

[MarkA]

I think I'm mistaken. Must be ablr's.

E tip is green, its ABLR

 

[AZlongrangehunting]

I suspected the copper fouling was giving me a smaller reading so I went from. 277-.279 to .2815-and with force .282 at the very tip of the muzzle and yes none of these were on the rifling after cleaning copper
Consistently .281-.2815 and with some force I'm getting .282 flashing .283 which to me again if they are calipers... can easily be off .002 but I rocked them and side to side to swing and measure to get it to .284 and it will not but this is the very tips of the calipers and the very tip of the barrel If I go inside the barrel it will never hit this just .281 .2815 but I have to put too much pressure to hit .282

 

[AZlongrangehunting]

Heres the case capacity numbers empty and filled norma has 84.5gr of water and hornady 83.5gr of water also converted to grams in the pic

 

[AZlongrangehunting]

Have any/many of your cases had black or sooty necks? If they have that would point to a carboned up chamber/neck area like mentioned above.

There is some soot present yes not covered just in spots on the cases

 

[lancetkenyon]

Did you chrono your loads?

I have done load development on 16 or 17 28 Noslers. I always used to start load development at 85.0gr. Almost every one finishes out at 87-89gr of RL33 to attain 3090-3160fps. I did have one however that had a tight bore and when I started at 85.0gr, I got ejector marks, heavy bolt lift, and almost 3200fps. I ended up at 83.0gr for that particular rifle to achieve a safe load at 3100fps. Cases were within 1gr of every other Nosler brand 28 Nosler brass I have used. Primers were from the same lot, powder was from the same lot.

 

[fmuguira]

Lancet Kenyon, +1

Knowing velocity will be most helpful... too much velocity over reasonable cartridge range equates to excess pressure... and in that case less powder could bring it all together.

Good observation!

 

[Bob Wright]

I live out by the White Tank mountain area in the west valley if you are in AZ. I can help with some basic inspections, have Cerrosafe, micrometers and a lot of experience on 7 mags. Would be willing to take a look at it if it's convenient for you. Something is way off somewhere. Don't trust those calipers in the bore to get an accurate measurement, just rough numbers.