My New 284 Build and Chrono results

[DennisH]

Below is a pictures of my new 284. I am still developing a load for it. I only shot these rounds @ 100yds to get the chrono results.

Below are pictures of the Chrono printouts. I don't know if my Chrono is broke, but the results change with every load.

Has anyone experienced the same results that my 55.5 load is showing? Going from 54.5 to 55.5 grns pushed the bullet over 200fps faster, 4831SC. ? ? ? Hard to believe .2 grains makes this much difference on the SD & ES.

180 grn Berger Hybrids, 4831SC, CCI LR primers, Lapua brass

Savage PTA action, SSS evolution trigger T&T'd by SSS, Heavy McGowen 28" 9twist barrel, SSS Heavy BR stock

Just need your opinions.

The 284 rifle:

54.5 load, 3 rounds, brass and primers looked good

55.5 load, only 4 rounds, brass and primers looked good, no pressure signs

55.7 load, 5 rounds, blew one primer, others showed slight pressure signs, to hot

 

[Steve Blair]

Dennis, [br]
2970 fps seems fairly stiff for a .284 Win. I get 2940-2950 from my .284 Shehane and 32" barrel. The cases are toast after 5-8 firings. I assume that you'are shooting 180 Hybrids?

 

[DennisH]

Steve, yes, I am shooting 180 Hybrids, .050 off the lands

Are you stating I should stick around the 2,925fps range? My ES and SD should be ok at this speed.

I am going to try some loads in the 54.8 to 55.4 range this weekend, FYI

 

[Steve Blair]

Even 2925 seems a little hot from 28". My current load is 57.4 grains H4831 SC, in a Shehane. I would expect 54.5 H4831 SC to produce ~2870 from a 28" barrel. You may have a fast barrel, so your load development should determine the optimum. I look for a .3-.5 grain range where the ES, velocity and accuracy do not change much. That is where you want to be. Those few FPS are not worth trading away the "sweet spot."

 

[DennisH]

Steve, Thanks Again,

Like I stated above, I am going to try loads starting at 54.8 and up. I will post an update.

 

[FroggyOne2]

I know that the others are saying that it seems that your going too fast or "hot" for the round.. just remember also, you may have just lucked out and have a fast barrel.. I would considered going by what your brass is telling you is too hot or not.. not the velocity of the bullet.. the bullet don't care, but the brass does!

 

[Immike]

I just started using a 284 win this summer with 180 hybrids, I settled on 55.94 gr of 4831sc pretty quick after testing. When I went to the natls I was told by experienced shooters that 55.9 is a common charge for that cartridge. I couldn't tell you the speed for certain but it's accurate! Mike

 

[birdog]

How did your groups look at 100 yds.
My smith shipped me a barrel out today
so I am interested in your group size also.
Your SD sure looks good!!!

 

[Mark Walker in TX]

My input is you likely have a chrono problem. The first set of data looks normal for a .284, while the next two are WAY above what folks get with a .284 and a similar charge, not to mention 1g of powder will not give 250 FPS more, its more like 50-75 feet more...

 

[habu]

mark,
have a tentency to agree with you. however, have noticed a couple of things that maybe a 'cause'.
1. CCI LR primers? - are these cci BR primers - i question them. i use fed 210m only! maybe cci BR in a pinch - NEVER a standard CCI. with the 1g+, primer MIGHT give those results.

2. WHY THE NEED FOR SPEED? and 'very small SD'? WHAT ABOUT GROUPS???

I personnally will take a 'slow' .2 MOA group [with an SD of 10] over a .5 MOA and a low SD.

i confirmed years ago that extreme acc. and ext. low SD don't necessarly go hand in hand.

FWIW i shoot for groups, then, maybe, will see how fast it's going!

ron

OH, and one other thing - why .050 'off' the lands when almost everone i know run about .015 'off' - 'lots of powder and bullet jammed way back + ? primmer"?????????

 

[FroggyOne2]

It is not the need for speed as you say.. it is where ever the best node is.. and if the best accuracy node is at the top of the speed spectrum.. Then it would be like "purposely stubbing your toe" because you like the pain, if you went a lower speed that was not quite in the accuracy node.. it is after all, all about winning. We may say to the different.. but lets face it, everyone likes to win. Just like barrels are a replaceable item, they get used. It would not matter what round I was using, I am going to use the best accuracy node the rifle has subject to the reloading components I have.

 

[jsimonh]

I replied to your thread on savageshooters, and will here also. A fast barrel is one thing, but nearly 3000fps is crazy out of a straight 284 w/4831sc. Mine ran 2860ish from a 28" barrel and I thought that was great. I'd re-chrono or use a different one and see if anything changes. If that's truly your speeds then you got a helluva barrel!

 

[Nomad47]

2870 MV with a 28" barrel, 54.5 H4831sc and 215M primers. Any more powder and I get pressure signs.

And I'm going to back the load down to 54.2 grains. QL and Chris Long's OBT say that should be the sweet spot.

 

[KT]

Dennis,
It looks like you need to take a look at the chrono. You gained 200 fps with one grain of powder. That is a bit much. Do you know anyone else that has a chrono you can verify with.


KT

 

[DennisH]

54.5 produces 2,750 fps, ES of 5.62 and a SD of 3.00. Very accurate at 100 yards

How did your groups look at 100 yds.
My smith shipped me a barrel out today
so I am interested in your group size also.
Your SD sure looks good!!

I know it's only 4 shots, but an SD of 0.00, well I have never seen this. And yes, I do have friends that have chrono's, so I will verify the speeds with their's.

From all of the comments above, it sounds like I need to find a load around 2,875fps.

As far as setting my Hybrids .050 off the lands, I have two other guns that like them off the lands this far. I just tried it one day and it tightened up my groups.

Thanks for all the above comments, I am studying all of them.

I am interested in more. At 54.5, the gun shoots great and shows no pressure signs. I guess the only thing I can do is see how this load affects my brass. I am going to load some up starting at 54.8 up to 55.4 just to see the results. I will also try some .015 off the lands on the smaller loads, 54.8 & 55.1, infact I will load up two sets just to see the exact difference.

Dennis

 

[DennisH]

Check the below link out, I have a picture of my targets posted there.

http://www.savageshooters.com/showthread.php?19614-My-New-284-Build-and-Chrono-results

 

[FroggyOne2]

Dennis,

I would be curious as to how the references will turn out with another chrony.. I love the group on the right and I can admit, that as long as the load was not hurting my brass, I would indeed run with that load and never look back..

Randy

 

[DennisH]

Randy,

This is the key. I am not showing any pressure signs on the brass, the groups are good, and the SD is definitely good.

I'm definitely going to try another chrono to make sure. I would definetly want my brass to last more than 6 rounds, so I hopefully will find a node in the 2,800 fps range.

About a month ago I compared my chrono with another one. They were both on the money!

Dennis

 

[FroggyOne2]

I have a feeling that it is around 2830 fps. Just a guess.

Randy

 

[DennisH]

I am wishing to get good chrono readings around the 2,900 fps area, maybe 2,925.