Factory Ammo Pressure? T3x 6.5cm Hornady 147 ELD-M

[TX_Diver]

Switched to factory ammo in October and have been getting random shots that have ejector marks and hard bolt lift. Usually it’s 1 or 2 then back to normal but yesterday after 3 in a row I stopped.

It does not affect velocity as 2 weeks ago I was shooting over a chrono and had it happen then for 2 rounds.


Stainless T3x. Factory barrel cut to 19” with a harvester evo on the front. Hornady Match 147 ELD-m all from the same lot. 2479 fps average. ~800 rds on this one

The rifle has never been cleaned but it’s no different than my .223 which has probably 2-3x as many rounds on it.


Time to clean? Other? I know others on here never clean rifles, and my .223 is probably close to 2x the round count as this one with no cleaning and no issues. I make zero effort to baby the rifle but can’t imagine I’m rougher on stuff than average.

Open to ideas. To rule out a few things, all same lot of ammo, has happened in temps from 30-80, I’ve left rounds in the sun before to ensure there’s no problems and they are fine. Yesterday it was ~45 degrees. No difference in time in chamber before shooting either for these.

 

[hereinaz]

Cleaning isn’t an issue until it is. I’d clean it paying attention to the throat. Cleaning won’t hurt the gun. I don’t clean much, but I don’t ignore my chamber.

Another possibility, the primer doesn’t look like it has pressure signs. Primer looks round and no cratering around the firing pin. I don’t think I have ever seen pressure show on brass but not the primer.

Is the chamber polished or oily? Brass oily/wet? If you don’t get enough friction between the brass and the chamber it pushes back into the bolt face. It can look like that.

 

[TX_Diver]

Cleaning isn’t an issue until it is. I’d clean it paying attention to the throat. Cleaning won’t hurt the gun. I don’t clean much, but I don’t ignore my chamber.

Another possibility, the primer doesn’t look like it has pressure signs. Primer looks round and no cratering around the firing pin. I don’t think I have ever seen pressure show on brass but not the primer.

Is the chamber polished or oily? Brass oily/wet? If you don’t get enough friction between the brass and the chamber it pushes back into the bolt face. It can look like that.

If it wasn’t pressure would I still see hard bolt lift?

Brass isn’t oily. Don’t think chamber is but I’ll clean it and check it out.

I’m not anti cleaning but if I don’t have to then I’m definitely not going to spend time cleaning just for it to look nice.

 

[hereinaz]

If it wasn’t pressure would I still see hard bolt lift?

Brass isn’t oily. Don’t think chamber is but I’ll clean it and check it out.

I’m not anti cleaning but if I don’t have to then I’m definitely not going to spend time cleaning just for it to look nice.

Yes, it can see hard bolt lift, because it pushes back as it expands. That’s why you have the swipe across the extractor mark because the case has expanded and it won’t go forward.

I don’t know all the causes and whys, but that’s what I would start with.

I am the same way with cleaning.

Look it up, but I think you can hit the chamber with some scotch brite or something to give the chamber some “grit” to hold the case in there. Seems that I have read that solved the problem for others.

 

[Mangata]

There is another thread on RS that was aimed at this exact same situation with no conclusion found. I have a T3x super light 6.5 creed that does the exact same thing with factory 147 ELDM. Mine has done it since it was brand new with less than 40 rounds through the barrel so I doubt carbon ring or cleaning issue. As I recall the 147 ELDM was the most common ammunition to cause heavy bolt lift & ejector swipes.

 

[dieselchessy]

Have folks measured OAL of the ammo and throat of the rifle?
May be that the bullets ojive shape and rounds OAL has it against the lands on some rounds and not others creating the over pressure.

Might be folks shooting factory dont have the tools to check?
A sharpy might be the only tool you need, but if they arent jammed, might not show with sharpy.

Are the unfired rounds tight when closing the bolt?

 

[T_Widdy]

Have folks measured OAL of the ammo and throat of the rifle?
May be that the bullets ojive shape and rounds OAL has it against the lands on some rounds and not others creating the over pressure.

Might be folks shooting factory dont have the tools to check?
A sharpy might be the only tool you need, but if they arent jammed, might not show with sharpy.

Are the unfired rounds tight when closing the bolt?

My tikka ctr 6.5 CM lands measured .135” jump from the factory loading of 2.800” coal with the 147’s

 

[ResearchinStuff]

Is it beating up those cases without firing? My t3x 6.5 creed makes ejector swipes just from cycling rounds through it

 

[wind gypsy]

Was wind in your face by chance? Ive had factory ammo do the same in a tikka 6.5 barrel but it was when cool and breeze was in the face. I thought it might be due to some condensation in the chamber after remembering this thread. https://rokslide.com/forums/threads/suppressor-causing-chamber-condensation.367653/

In the same session I had zero issues with an 18” suppressed 223 that had more rounds on it since cleaning. Chalked it up to the 223 generating less heat, condensation, and bolt thrust than the 6.5.

I’m not sure if condensation was the cause or not but it’s a hypothesis. In my case it was with both Berger and Norma factory ammo and showed 100% heavy bolt lift with both. I did clean the 6.5 barrel after as it had been 3-500 rd since it was cleaned. No heavy bolt lift on following range trips.

 

[Mangata]

I have found nothing to correlate prior to firing a round to predict heavy bolt lift and ejector swipes. I used a sharpie on a box of 147 ELDM this morning. None of the rounds had any difficulty chambering and appear all similar after ejection. Have not fired as of yet.

 

[SDHNTR]

Sharpie up the shoulder of the brass. My bet is you’ll get a few every so often that are either too tight, which would show in the sharpie, or even have excessive slop. Either can cause ejector marks. Or better yet, get a caliper and some headspace comparators and measure.

 

[NWBLKTAIL]

^ I order 300 rounds of 147eldm when I got a tikka t3x roughtech in 6.5cm.

Same thing occasionally hard bolt lift and ejector marks. Shot fantastic.

Shooting a box one day and could not chamber a few rounds due to long shoulders. That were verified with Hornady headspace guages. .010” long. Still have the round need to pull the bullet.

I never really came to a conclusion about the “why” it was happening. But never really dug any deeper because I wasn’t the only one experiencing it from what I was reading.

 

[Mangata]

Appreciate the suggestion!

I guess at this point my question is; if accuracy is not affected and there is no significant difference in MV then are 3/20 rounds with sticky lift & ejector swipes worth chasing???
Ultimately it would be avoid the 147 ELDM factory load or live with the above three rounds or so out of each box.