180 Berger Hybrid Seating depth - .284?

[DenisA]

Hi Guys and Gals,

I'm about to start load development for a .284 and I'm using Berger 180g Hybrids. I'll be starting at 52.9g of AR2213sc and testing out to 55.3g, in .3g increments.

Obviously all guns are different and I will identify the best for this barrel, but I'd like to know how much others are jumping or jamming this projectile for best results.

Thanks in advance for your input.

Denis.

[DaveMc]

Small jump for me seems to work Denis (<10 thou). But I have heard of everything from jam to well over 100 thou jump.

[RDavies]

I have used them in 6x 7mm barrels.
1x 284 much prefers them about .005" jump
2x 284 prefers them .015" jump (same reamer as other barrel)
2x short mag wont shoot them until they have at least .090" jump (same as another short mag shooter I know)
Newest short mag will only shoot with them jammed .015" (same reamer as barrel which needs them jumping a long way).

I have heard all about how these bullets are so easy to tune and seating depth insensitive, but I have found they have definite jump/jam preferences for each barrel. A FEW of my barrels including 6mm and 6.5s, got better accuracy with the VLDs, and others have found the same, so be prepared to experiment if you dont get the accuracy you want.
I kind of think that when people say the Hybrids are seating depth insensitive, they will give you 1 moa accuraccy with any seating depth, but to get down to the accuracy you need to stay in the X ring, then you might need to experiment with them a lot. With VLDs, jam them 10-15 thou and thats it, go hammer the X ring.

[DenisA]

I have tried the 6mm 105g Hybrids in my 6BR and went back to the VLD's. I found the 6mm Hybrids were too finnicky so I know what you mean. I have been told and hoping its true, that the larger cal. Hybrids aren't so sensitive.

I did the checks last night, and to get a .005" jam I only have about approx 4mm (.160") of bullet shank in the neck. That doesn't concern me being a new barrel, but once the throat starts to errode I may not be able to comfortably maintain a desired jam.

I fireformed and broke the barrel in with 150g Nosler Ballistic tips jammed .005". The diiference in ogive shape allowed plenty of shank in the neck.

How much shank are you guys seating in the neck?

[AlanF]

Denis,

I have a long free-bore reamer (0.239) and have at worst to date (with the hybrids jammed after about 1000 rounds throat wear) about half the neck engaged on the bearing surface. I don't see it as a problem. The throat is not receding dramatically in this calibre. If you're concerned about neck tension, use a tighter bushing.

Alan

[DenisA]

Denis,

I have a long free-bore reamer (0.239) and have at worst to date (with the hybrids jammed after about 1000 rounds throat wear) about half the neck engaged on the bearing surface. I don't see it as a problem. The throat is not receding dramatically in this calibre. If you're concerned about neck tension, use a tighter bushing.

Alan

Hi Alan,

I'm not too worried about it and have multiple bushings so I can follow your suggestion if any problem starts to arise.
Being square cut lands, I'm expecting them to deteriorate quickly and having no experience with a .284, I suspected that it will be a lot faster than my 6BR erroded.

My concern was that it woud be a shame to develop and find a jammed load and then have to find a jumped load later.

Thanks for your experience, much appreciated.

[bruce moulds]

as rod says.
keep safe,
bruce.