6 Creed Berger 108 EH Load Info - Pressure Early?

[SloppyJ]

Took my 18" 6 creed out last weekend to break it in. I shot 70rds through it over the course of the day. I tested 108 ELDMs and 108 Berger Elite Hunters. Thinking they would roughly be the same, I loaded up 50 Bergers at 41.8gr of H4350 in new Peterson SRP brass with CCI 450s which is near the book max of the ELDMs. These were going to be my long range steel loads to play with. I loaded 25 powder test loads of both the ELDMs and the EH to see if I could find pressure and get some velocity data.

Well to my surprise I started seeing heavy bolt lift around 40.5gr with the Bergers. I shot 5 of the 41.8gr loads and they grouped really well and had an ES of 18 and a SD of 10. No denying the sticky bolt lift but no cratering of the primers. I was at a range that I'd been waiting to go to for a while so I sent them all collecting velocity and checking my dope. I ended up running through all 50 of them. Walked out from 300yds to 1100yds.

I didn't get to test all of my other powder charges with the two bullets but I had no pressure signs with the ELDMs at 40.5gr. Those shot around 2860fps and the 41.8gr Berger loads averaged 2898fps. Bergers were 50thou off and the ELDMs were 30thou off.

The velocity seems to be there but the powder charge seems low to me. I'm roughly a full grain short based on both Hornady and Hodgdon's data. It's probably 1yr old H4350 that I'm using if it matters. Trying to figure out what could cause this and if it might be worth to try some N555 in there to see what I can do since I still have case capacity left.

 

[wind gypsy]

You're using peterson brass. Hornady and hodgdon data use hornady brass. Peterson has less capacity than hornady. It's showing pressure probably because there is pressure.

Is it a saami chamber?

 

[Lawnboi]

There’s a number of things that could be going on here.

Is this a fresh barrel? I normally don’t test for pressure to the edge until the barrel is broken in. Normally starting with a fairly low charge weight. It’s not uncommon to see a barrel speed up, if you’re on the edge of pressure off the bat I have seen that cause issues as it speeds up. The first 100 rounds speed is to assess the barrel speeding up, that is all.

Also not uncommon for a new barrel to be hard on brass for a number of rounds. I have seen this on factory and custom barrels.

Peterson brass has way less volume than the Hornady that Hodgdon pressure tests. Your loads are likely hot.

I would back it down, break in the barrel and then test for the speed you want. That said personally I think the 6 creed especially with srp runs best at lower pressure. Personally I keep it around 40g of h4350 for that bullet range.

 

[SloppyJ]

You're using peterson brass. Hornady and hodgdon use hornady brass. Peterson has less capacity than hornady. It's showing pressure probably because there is pressure.

Is it a saami chamber?

Yes saami chamber. I figured it would be a bit thicker causing some sort of divergence from the standard load data but I typically always use Peterson stuff and haven't had one this far under book max. Maybe on most older cartridges they're even more conservative which is why I don't have the issues.

 

[SloppyJ]

There’s a number of things that could be going on here.

Is this a fresh barrel? I normally don’t test for pressure to the edge until the barrel is broken in. Normally starting with a fairly low charge weight. It’s not uncommon to see a barrel speed up, if you’re on the edge of pressure off the bat I have seen that cause issues as it speeds up. The first 100 rounds speed is to assess the barrel speeding up, that is all.

Also not uncommon for a new barrel to be hard on brass for a number of rounds. I have seen this on factory and custom barrels.

Peterson brass has way less volume than the Hornady that Hodgdon pressure tests. Your loads are likely hot.

I would back it down, break in the barrel and then test for the speed you want. That said personally I think the 6 creed especially with srp runs best at lower pressure. Personally I keep it around 40g of h4350 for that bullet range.

I'm backing down to my 40.5gr load with ELDMs for my match next weekend. I had good ES and SD numbers with those. After those 100rds, for a total of 170rds, I should be nice and settled in barrel wise. I'll run my chrono the whole match and see what I come up with.

 

[Lawnboi]

I'm backing down to my 40.5gr load with ELDMs for my match next weekend. I had good ES and SD numbers with those. After those 100rds, for a total of 170rds, I should be nice and settled in barrel wise. I'll run my chrono the whole match and see what I come up with.

Good plan.

Last I broke in a barrel during a match I saw 80fps between rounds 100 and 200.

Thank god for Garmin.

 

[B_Reynolds_AK]

FWIW, I put 120 rounds of factory Hornady Black and 108’s through my current 6 CM barrel before doing any load dev. I had heavy bolt even on a few factory rounds during that time. Alpha brass and LRP’s with H4350 are what I use and I ended up at a load nearly a full 2 grains above your ELD-M load.

 

[HGL]

I worked up some loads for my 6CM with Peterson LRP brass, so not a perfect comparison. It's a Tikka with an 19" Osprey barrel, 1-7" twist.

Using Perterson LRP, H4350, CCI-BR2s, and 108 ELDMs kissing the lands, .005" jump. Below were my results:

40.8 gr - 2892 fps, no pressure signs
41.1 gr - 2945 fps, no pressure signs
41.4 gr - 2997 fps, slight ejector marks, primers looked fine
41.7 gr - 3007 fps, ejector marks and heavy bolt lift, primers looked ok, maybe very slight flattening.

So it kind of mirrors what you saw with the Bergers.

The 41.1 gr load shot great, so I'm going to do some verification at distance with that.

I've also got a very accurate load with RL-26 and the 108 ELDM @ 2995, but I'm about out of the pixie dust.

 

[SloppyJ]

FWIW, I put 120 rounds of factory Hornady Black and 108’s through my current 6 CM barrel before doing any load dev. I had heavy bolt even on a few factory rounds during that time. Alpha brass and LRP’s with H4350 are what I use and I ended up at a load nearly a full 2 grains above your ELD-M load.

That makes me feel better. I don't want to run the piss out of it but I wouldn't mind a solid 2875. I'm going to try this thoroclean system on it and see how it goes during the match. I'm hopeful that it will level out some more and get some more bandwith in the charge department.

 

[SloppyJ]

Good plan.

Last I broke in a barrel during a match I saw 80fps between rounds 100 and 200.

Thank god for Garmin.

What'd you see between 0 and 100? I think I'm sitting around 65fps going on my 71st shot. I was expecting it to level off but maybe not now after what you said.

 

[Lawnboi]

What'd you see between 0 and 100? I think I'm sitting around 65fps going on my 71st shot. I was expecting it to level off but maybe not now after what you said.

If I remember that barrel was 30 or so fps the first 100.

My latest 6 creed went 100 fps the first hundred rounds and has been consistently 20 fps every match since

 

[wind gypsy]

That makes me feel better. I don't want to run the piss out of it but I wouldn't mind a solid 2875. I'm going to try this thoroclean system on it and see how it goes during the match. I'm hopeful that it will level out some more and get some more bandwith in the charge department.

2800ish is where I settled with a 18" with Alpha LRP and H4350 with 106-109s. Alpha brass has more capacity than Peterson. Probably leave it around 2840 with 109s and N555 for my hunting load this year. Even with that, i seem to come up on sticky bolt lift once I'm 75+ rounds since the last barrel cleaning..

Also, have you seen this thread? https://rokslide.com/forums/threads/6cm-clickers.355604/page-5

 

[Lawnboi]

2800ish is where I settled with a 18" with Alpha LRP and H4350 with 106-109s. Alpha brass has more capacity than Peterson. Probably leave it around 2840 with 109s and N555 for my hunting load this year. Even with that, i seem to come up on sticky bolt lift once I'm 75+ rounds since the last barrel cleaning..

Also, have you seen this thread? https://rokslide.com/forums/threads/6cm-clickers.355604/page-5

I think this is exacerbated by alpha brass. I don’t know what the deal is but I seem to always have issues with alpha eventually that go away when using Peterson or lapua.

 

[wind gypsy]

I think this is exacerbated by alpha brass. I don’t know what the deal is but I seem to always have issues with alpha eventually that go away when using Peterson or lapua.

I'm pretty sure I saw it with Lapua brass and definitely saw it in Sig and Hornady factory ammo as well though.. The sig match 107 SMK ammo shoots good, avg around 2800 in my rifle (18") and starts getting sticky after some fouling comes on.

 

[SloppyJ]

Thanks for the link Wind Gypsy. I hadn't seen that thread before.

I was at my in-laws this weekend and I had my gun and chrono with me. I fired off 5rds of 108 ELDMs at 41.5gr H4350 and my velocity average was 2928 with single digit SD and ES. Had sticky bolt lift on the last two for some reason. It was also 95 degrees outside so that didn't help. I cleaned the gun the next day and it wasn't too dirty but I'm hoping some of that was a contributing factor.

I resized and prepped another 100rds of new Peterson SRP brass for my match over this weekend. Decided to forego the velocity and load them somewhere super safe around 40.2gr H4350. I also ordered some N555 to give it a shot since I have plenty of case capacity left. Been wanting to try some VV powder for a while and I got some N570 for my 300prc while I was at it.

 

[SloppyJ]

I shot a match today and feel like my barrel is broken in now and I got some speed.

I loaded 108eldms with 40.2gr of H4350 to be safe which is way below book max. The last 10 shots were off a bench at 500, 600, 800, 1000, and 1100yds. I chronoed those rounds and ended up with 2888fps with a ES of 14 and a SD of 9. That's with 170rds down the barrel and that's smoking fast with that powder charge compared to book values. Again, this is an 18" barrel. It was also touching 100 degrees today.

All this to say, peterson brass has much less capacity than the hornady stuff that's used for load data so be careful. This is the biggest swing I've seen yet as a reloader.

I decided today that if I'm going to continue shooting matches it will be with a different barrel and stock so I'll see where that goes. A 10lb rifle doesn't belong in a prs match if you're looking to be competitive. But you gotta use whatcha got.