IMR 4064

[archad]

Thank You. Rifle specs please?

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[Krazykarl]

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[Krazykarl]

Had to purge my inbox and free up space. The above handwritten notes come from my research on a Bergara 6.5 creedmoor with a factory 18" barrel. The barrel is free floated in a KRG chasis stock. All test groups are n=5. All test groups were fired to magazine COL 2.831". The test was intended to determine preferred bullet weight using Hornady 123 sst vs Sierra 142 MK. Powders tested in 0.5 grain increments were IMR 4350, IMR 4064, and Varget. Winchester LRP used for all in Hornady once fired brass. Group size is noted next to each Oehler data summary. No difficult extractions and no excess pressure signs. Testing done at 100 yards and weather was typical for NW Indiana. Cold and windy over 5 days....

[markm]

IMR 4064 has been a constant companion in my family with great results. The only negative experience was 6.5 Swede in the m96. IMR 4064 was too fast for the 29 inch barrel producing a smoking action and carbon streaking on the brass. I switched to IMR 4350 and got better results and the pressure stayed high enough and long enough for the bullet to leave the barrel AND keep the brass sealed against the chamber walls. I am home now and will provide my results of the 6.5 Creedmore..

That's interesting. We run a lot of relatively fast powders, but no extra long barrels.

[Krazykarl]

Pretest bias is a real problem in testing. I was a trained scientist and I still had certain expectations for this rifle. I really wanted the IMR 4064 to work for me. I believed that the shorter barrel would excel with the faster powder and lighter 123 gr bullet. The IMR 4350 seemed ill suited for an 18 inch tube. My data above proves me wrong. I see four conclusions:
1. IMR 4064 made good precision but poor velocity.
2. 1:8 twist barrel optimized for 142gr bullets did not like 142gr bullets.
3. IMR 4350 near maximum load with 123 bullets is the chosen one for acceptable precision and velocity. I read somewhere that a maximum load of this powder did produce the best precision. I will have to deal with the well documented temperature sensitivity of IMR4350 later.
4. 6.5 creedmoor has proven to be a little tricky for me to work up loads. I think I read that Markm had the same sentiment.

[turnburglar]

Wait you said you got good results with IMR4350 and 123's?

I checked Hogdon reloading website and it doesn't show that powder bullet combo.

I would like to shoot lighter bullets in the 110-123 range because my local matches dont typically go past 700 yards. What powder would you recommend? I have an 18" barrel I worked up a 41.5gr of IMR4350 under a 140gr hornady and it makes about 2600 FPS.

I am re-barreling the rifle soon to a 16" cause I am adding a can and dont like my 18".

I currently own IMR4350 but am trying to get BLC2 or staball 6.5.

[Krazykarl]

With IMR 4350, 44.0 grains and 123 SST, I measured 2690 fps and 1.0" 5 shot group including the outlier. My rational for stating acceptable velocity is based on the article found in snipeshide.com where a 6.5 creedmoor was cut down incrementally and chronographed. The author reported 2761 fps with a 120 gr bullet and 18"barrel. If memory serves...

[turnburglar]

I didn't read the article but did it say if he was using the same powder? To me ~2750 from an 18" seems smoking fast.


I was recently wondering what the optimum load for a short barrel 6.5 is. I get that most of the precision loadings are for longer barrels, but I bet with the right powder selection the short barrels could do well. For the record I mean 16 - 18" barrels are 'short' for the 6.5 creed moor. Also this "optimum" load would have to be from components that are not unicorns in the current climate.

[Krazykarl]

The referenced article uses a factory loading of 120 AMax. I used his chronograph as a single benchmark of the potential velocity possible with light bullets (120 gr) and a short 18" barrel. My load got close to his velocity using my components with no excessive pressure signs.

I was able to digest three different data sources of IMR 4350 with 120/123gr bullets:

1. Start 40.0 grains. Max 44.0 grains. 2950 fps from their test barrel.
2. Start 40.5 grains. Max 44.4 grains.
3. Max 44.0 grains.

I went as high as 44.0 grains and achieved 2693 fps. Maybe I might push a little more..

[turnburglar]

Hey thanks so much. Im gonna pick up some 123's my buddy doesn't mind loaning out and make a test ladder starting at 40.0.

Almost forgot to mention that I am shooting a gas gun. A bolt gun could probably achieve higher velocities no problem-o.