Safe or not safe to reseat my OAL alittle shorter?

[The ROC]

Need advice....

I will be shooting the ISPC Ontario Provincials on July 3rd, next Saturday. I was planning on using my M&P9 with my handloads, 250 rds: Frontier 147gr CMJ FN, 3.9gr TG, OAL 1.130"

I just bought a CZ Shadow and I shoot way better with it over the M&P9. I want to use the Shadow for this match instead. Because I reload with a single press I was hoping to reseat my handloads down to a OAL of 1.060" instead of making up a whole new batch.

Can I do this without cause unsafe pressure?

Unfortunately I don't have the time to visit the range either to test for signs of excess pressure.

Thanks for the help.

Edited June 26, 2010 by The ROC

[Sarge]

That sounds like too drastic of a change.

[atbarr]

Not a good idea.

A.T.

[Pat Miles]

.070" is a bunch when it comes to reloading. You will very probably cause a spike in pressure doing so. Be safe...DON'T DO IT!

CYa,

Pat

[The ROC]

.070" is a bunch when it comes to reloading. You will very probably cause a spike in pressure doing so. Be safe...DON'T DO IT!

CYa,

Pat

Thanks.... Just curious, would shortening the OAL by 0.030" be a lot or would that be on the safe side?

Edited June 26, 2010 by The ROC

[Pat Miles]

.070" is a bunch when it comes to reloading. You will very probably cause a spike in pressure doing so. Be safe...DON'T DO IT!

CYa,

Pat

Thanks.... Just curious, would shortening the OAL by 0.030" be a lot or would that be on the safe side?

.030" is still a goodly amount. I sure wouldn't do it without being able to check a few that have been fired for over pressure. Be safe...don't.

Pat

[Aircooled6racer]

Hello: You may be able to load those in the mags. I can't remember what length I used to load mine to. I think 1.150". What I did have to do with the CZ Shadow I had was throat the barrel to allow enough room for the bullet profile I was using. You may want to have that done so you can use a longer OAL. The Shadow I had was a tack driver but I couldn't get used to the double action first pull Thanks, Eric

[G-ManBart]

I wouldn't try either .070 or .030" of change, for a couple of reasons. First off, I haven't seen much data for a 147gr CMJ with Titegroup, but Speer does show a 147gr TMJ and they only show 3.3gr at around 864fps (1.130"). Hodgdon lists a load with the Hornady 147gr XTP, showing a max of 3.6gr at 929fps (1.100"). That means that at the very least you're already over the max, unless you've been able to find some other data.

Shortening the OAL on a case like 9mm that doesn't have a whole lot of case capacity to start with can cause some pretty significant increases and the problem is that there isn't any really safe/reliable way to predict what will happen. Now, if you'd said .010" of change, it would probably be fine if you weren't already seeing pressure signs.

Lastly, shortening rounds after the bullets are seated and the cases crimped can sometimes lead to terrible accuracy....just sort of hit or miss (pun intended). R,

[Loves2Shoot]

A customer of mine would not listen to me about shortening his already loaded ammo and the hazards of greatly increased pressures, so yesterday he came in to get yet another barrel replaced from over pressured reloads.

[gm iprod]

I have to agree with Gman Bart and everybody else for that matter. Other than for testing I have never loaded any 147gr bullet with anything more than 3.6gr TG and that was at 1.150", and it made minor easily.

During testing loads at 3.8gr showed some pressure signs, and I quit. At 3.9 and then loafing very short I can only see disaster.

Honestly unless you can get to a range use the M&P. You knowthe load is safe in that gun and work a new load for the CZ. It is only one match, don't make it your last.

[G-ManBart]

I have to agree with Gman Bart and everybody else for that matter. Other than for testing I have never loaded any 147gr bullet with anything more than 3.6gr TG and that was at 1.150", and it made minor easily.

During testing loads at 3.8gr showed some pressure signs, and I quit. At 3.9 and then loafing very short I can only see disaster.

Honestly unless you can get to a range use the M&P. You knowthe load is safe in that gun and work a new load for the CZ. It is only one match, don't make it your last.

Something just popped into my head...at least some Frontier bullets are actually plated, not jacketed. From their website, it appears the 147CMJ-FP is plated, which would lower pressures significantly, and maybe 3.9gr isn't unsafe. Since plated bullets tend to run similar velocity to cast lead I wouldn't think it necessary to go to 3.9gr to make Minor. R,

[Jody Waring]

If you don't have time to experiment, I would just shoot the M&P as that is what you are currently using, your ammo is loaded for it, and experimenting last minute with ammo for me has always been a mistake. That load sounds a little hot to me with the 147. A friend of mine I am pretty sure only loads like 3.6 or 3.7 of 231 and I believe 231 is a bit slower than Titegroup. When you are ready to start shooting the Shadow regularly, I would spend time working up a load and get everything just right, correct OAL, etc... and make sure its reliable. I wouldn't rush into it last minute just so I could shoot a match. My Shadow with 124gr Frontiers engages the rifling even at 1.145" so I am now loading at 1.115" and I backed of .1g and it shoots great, feeds good and I have no signs of overpressure. Winchester FMJ allows me to load longer as the profile is more tapered. In Ontario you are fortunate to have many shooters using CZ's I would take advantage of that and get all the input you can and ask what others what they are using for ammo. Good luck.