HUGE velocity difference between primers

[CZ527]

I loaded about 25 rounds for my .223 to test the difference between federal 205 primers, and remington 7 1/2 BR primers. The remington primers shot about 1/4 inch better groups, however when chronoing them they were 550 fps slower than the federals. With the remingtons, 40 grain vmaxs, and 26.5 grains of H4895 the 5 shot average velocity was 2850fps. With the federals, and the exact load with everything the exact same from the same gun on the same day shot 3400fps. According to my Hodgden reloading book that load should be doing 3200fps. What's the deal??? A 550fps spread in velocity seems crazy. That isn't normal with benchrest primers, or remington primers is it?

 

[Spotcheck_Billy]

I'd hazard a guess that unless you had an inadvertant mixup in your loads you've got chronograph problems. That's just a SWAG, but I can't think of anything else that would result in that kind of velocity deviation.

 

[CZ527]

I tested the chrono with other loads of known velocity as well. Those came out as expected.

 

[ghermitage]

I would like to know what results you get with CCI Benchrest primers, to see where they fit into this.

Got access to a second chonograph? Given the importance of this news, another check would be nice.

 

[MrCrowley]

Either something is wrong somewhere or it's a pretty big discovery you have come across.

 

[people]

You may just be lucky I guess.

 

[acloco]

What chronograph?

500 is a LOT!

Most I have seen across my Pact is 110 fps.

There is something wrong here....per Hodgdon's site:

"40 GR. NOS BT 40 H4895 .224" 2.280" 25.0 3204 32,100 CUP 27.5C 3573 44,500 CUP "

26.5 gr of H4895 should be at or near the 3400 range.

Are you bullets moly coated by chance???

 

[wnroscoe]

I've tested several different primers in several different calibers with the same known load in each rifle. Federal 210M always gave the fastest velocity with the WLR close behind. Remington always gave the slowest. With my .308 as the test rifle, testing the 210M against the BR2, same load, there was only 10 FPS difference and the BR2 shot better. In my 6BR, the F205M has performed the best with the CCI450 close on it's heals. I have'nt tried the Remington's from my 6BR and probably wont, I feel that the velocity will drop off due to prior testing. I did find that after about 70 grains of what ever powder, the F215's out performed all others. I dont think your chrono is broken, I chalk it up to the Remington Primers just being much milder.

 

[Lane]

I loaded about 25 rounds for my .223 to test the difference between federal 205 primers, and remington 7 1/2 BR primers. The remington primers shot about 1/4 inch better groups, however when chronoing them they were 550 fps slower than the federals. With the remingtons, 40 grain vmaxs, and 26.5 grains of H4895 the 5 shot average velocity was 2850fps. With the federals, and the exact load with everything the exact same from the same gun on the same day shot 3400fps. According to my Hodgden reloading book that load should be doing 3200fps. What's the deal??? A 550fps spread in velocity seems crazy. That isn't normal with benchrest primers, or remington primers is it?

Keep in mind that chambers that are reamed with tight or close to minimum diminsions/tolerances will create more pressure with a specific load then a chamber reamed closer to the maximum chamber dimensions/ tolerances. Tight chamber pressure is higher, loose chamber pressure lower assuming all things are equal. It is my understanding powder companies and loading guides use pressure barrels with tight chambers for establishing pressure and velocity tests. The velocity and pressures listed are based on relatively tight chambers creating high pressure/velocity for that load listing. Bullet bearing surface,friction) with your specific bore/groove diameter would be another factor to consider. Some barrels are fast others slow with particular bullet weights/designs. I'm not saying this accounts for all your velocity deficiency, however the issues have to be considered relatively to any diagnosis in inconsistency in my opinion. The primer is just one part of the issue. Soft/hard primer cup, hot/mild primer mix. Lots of varbiles factor into any velocity lost or gained. Lane

 

[Linefinder]

Some barrels are fast others slow with particular bullet weights/designs. I'm not saying this accounts for all your velocity deficiency, however the issues have to be considered relatively to any diagnosis in inconsistency in my opinion. The primer is just one part of the issue. Soft/hard primer cup, hot/mild primer mix. Lots of varbiles factor into any velocity lost or gained. Lane

I agree. A friend and I have "twin" 6mm Rems with Krieger barrels chambered with the same reamer by the same gunsmith at the same time. Same barrel length, etc.....these two rifles are as close to clones as I think you can get. A charge of 49 grains of H4350 propels 75 grain VMaxes from my rifle at 3670 fps,Usual disclaimer here...safe in my rifle, but decidedly "warm"...not recommended without careful working up). I told my friend about this load, which has proven amazingly accurate for me, and told him to start out 4 grains less and work up.

He ignored that piece of advice, and loaded to 49 grains immediately. His rounds, from a "clone" rifle/barrel, clocked substantially over 3900 fps. While he didn't blow out any primers, they were flat as a pancake and you can now "seat" a primer with your finger on those 3 pieces of brass. Which is how many he fired before he concluded something was amiss.

To achieve the 3670 MV I was getting, he had to drop the powder charge from 49 grains to 46 grains. We checked the burn rate of his powder compared to mine via QuickLoad, and they were within 2% of each other.

Just goes to show you....

Mike

 

[Lane]

I loaded about 25 rounds for my .223 to test the difference between federal 205 primers, and remington 7 1/2 BR primers. The remington primers shot about 1/4 inch better groups, however when chronoing them they were 550 fps slower than the federals. With the remingtons, 40 grain vmaxs, and 26.5 grains of H4895 the 5 shot average velocity was 2850fps. With the federals, and the exact load with everything the exact same from the same gun on the same day shot 3400fps. According to my Hodgden reloading book that load should be doing 3200fps. What's the deal??? A 550fps spread in velocity seems crazy. That isn't normal with benchrest primers, or remington primers is it?

26.5 grains H4895 .40 grain vmaxs.,H4895) is this correct? Maximum average chamber pressure for the .223 Remington factory ammunition should not exceed 55,200 c.u.p. is this correct? Lane

 

[CZ527]

I've since tested the H4895 powder with 52gr bergers, and 60gr sierras, which both also shoot very slow as in 2700-2800 fps with a max load at 27.0 gr. Also tried winchester primers which shoot faster then the rems, but slower then the federals. The thing is shooting in the .3s with this these loads, but are going so slooow I might as well be using my 22 Hornet.

 

[Lane]

If you zero in on two traditional powders that have a history with the .223 Remington H-322 and Reloader # 7 both are faster burns then H-4895. X-terminator I would look hard at with it's high bulk density and metering qualities. I would suggest loading your components of choice matched with a powder with a faster burn rate and high bulk density. I sympathize with your problem! Lane