The Focus system sucks. So does the similars system from Altra arrows, Junk as well.
Here is what does work with 4mm. Pros and cons listed and in descending order of my preference. I have more money tied up in components an arrows then most, hopefully this will save you some time/money . Keep in mind fitment with deep impact, same as altra they aren't the most friendly OD to and components
~4mm steel or TI deep six hits with steel or TI collars. The collar must( more so in deep six hits) go past the hit by a decent amount. If you can suffer through just using deep six broadheads, This a great system. I am not willing to limit myself so I dont often use this. The same can be said for heads with fixed 4mm inserts that glue in. Great concentric option and strength however limited choices and pose some very real in the field issues. If you go with this the IW hits and collars are the way to go. They are precise and durable.
~Ethics AL/Steel outserts and collars. These are great options with some caveats. S/S versions are really too heavy to usable. The AL insert with steel collars are very good options however when you cut the posts down to get them to be usable weight you loose some durability. I feel that fitment aside a collar over the outsert is more durable than a collar over the shaft, in theory I can't see how this isn't so, In practice I honestly haven't seem a difference. Cons are expense and the weight.
~Victory collared outserts for VAP. They are very serviceable, they are reasonable priced. They come in enough sizes and weights to fit any shaft and build. They are easy to install and replace. Great value when your getting components that are actually usable( unlike focus and altra that go right in the trash) Down side is they aren't the most robust.
~Easton match grade 4mm, repeat everything above about the victory however they are more robust generally, they are also more expensive. However they are 100% serviceable.
~CMI TI / Steel 4mm outserts. These are very nice, especially in TI at fifty grains. They take back weights, they are durable and easy to install. I am working on pairing them with ti collar that will be installed below the insert. Downside are the costs they are expensive for what they are, and they are not OD specific.
~Podium two piece 4mm TI, these are a fantastic system, durable, relatively cheap for what they are, however if you're fitting a dozen or two it adds up quick. They will take a back weights, they come in three sizes to properly fit any shafts. Main downside is they can be picky on your install. Make 100% sure you face is square before you install the collar, only then install your insert.
~ TI outsert and collar from Ethics, these in 75 grains 100 grains are the gold standard. Performancewise they have no downside, they are the best. The do have two cons First any 50 grain version would be insanely popular and they dont offer it. Secondly they are stupidly expensive and I am not sure the cost vs performance is justified vs some of the options above.
