Possible IMR 4227 compressed .357 load.

[DBEAM]

I am currently loading hornaday 158gn xtps in 357 with IMR4227 following the loads in my speer 14 manual which starts at 15 grs and ends at 17 grs. The first load I did was 15.7 gns (1.26 on my lee auto disc) which looked as though it may have compressed some but was unsure.
Results from that were 993 fps average out of my rossi 462 and 1036 average fps out of my High standard 4 inch barrel MKII. Average fps out the MK II with federal jsps was 1195 for reference. I remember the reload cases dropping free easily from the Rossi but one was hanging up in the high standard, it would easily go in and out of another chamber in the cylinder though.
I have now loaded some to 16.8-17.0 (Lee auto disc 1.36) and noticed that it appears the powder has to be compressed by the time the bullet is seated from holding the bullet next to the filled case and eyeballing where it would be when seated at the crimp. COAL is around 1.580-1.583 and primers are cci 500s. The manual does not denote this as a compressed load.

My concern is that this is an compressed load either by error of the manual or by something I could be doing.

 

[243winxb]

357 magnum

15.3 gr Maximum load?? with a Rem 158gr jhp is being show as compressed (C) in the IMR 2006 data . From link below. My Target with cast.

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[cheygriz]

There is nothing wrong with compressed loads.

Many of my loads are heavily compressed.

 

[buck460XVR]

Many max loads in magnum handgun calibers when using IMR4227 will be compressed, this includes .357. My most accurate loads with IMR4227 are just at or just slightly above compressed.

 

[DBEAM]

Its my first time loading magnums. I saw loads listed as compressed with this power for a 125 gn jhp but for 158 its not listed as compressed. Maybe the speer bullets are shorter then xtps. Then I see 15.3 listed as max. I think Lyman list it even lower.

 

[243winxb]

Rifle data at Hodgdon's website has a load for IMR4227 & 158 gr bullets. 16.0 gr is listed as maximun. Work up as always.

 

[gamestalker]

Compressed loads in and of their self are not a concern or red flag. What matters is if the data is being used as published, if that results in a compressed load, than so be it.

Most of my .357 loads H110 / 296 are compressed. Same thing with high powered rifle, some published load data may not indicate a particular load / charge as being compressed, when in fact the charge is obviously compressed. It just depends on the publisher, and whether or not they either just omitted that characteristic, or in some instances, the publisher may not do their own testing, thus just using another publishers data.

So if your compressed loads are performing in a safe manner, I would deduce that everything is fine. And with the one firearm that the brass doesn't just fall out, it may be the cylinders are not as polished, or they may be slightly larger internally. And if they don't produce a lot of resistance when extracting them I wouldn't consider excessive pressures to be involved. I have one particular revolver that the brass never just flass out after firing, but it also has rough machining lines that cause them to hang up slightly after being fired.

It's when we compress powders with charges that exceed the published table that things become a concern.

GS

 

[DBEAM]

Could the reason speer is listing higher charge weights be because theu are using regular primers vs magnum primers?